Method for the preparation of a liquid crystal polymer film

ABSTRACT

The present invention relates to a method for the preparation of a homogeneous aligned liquid crystal polymer film, a polymer film obtainable from the corresponding method of production, and to the use of such polymer film for optical components and electro-optical decorative, as well as to components and devices comprising such polymer film.

FIELD OF INVENTION

The present invention relates to a method for the preparation of ahomogeneous aligned liquid crystal polymer film, a polymer filmobtainable from the corresponding method of production, and to the useof such polymer film for optical components and electro-opticaldecorative, as well as to components and devices comprising such polymerfilm.

BACKGROUND AND PRIOR ART

Polymerizable liquid crystal materials or reactive mesogens (RM) areknown in prior art for the preparation of anisotropic polymer films withuniform orientation. These films are usually prepared by coating a thinlayer of a polymerizable liquid crystal mixture onto a substrate,aligning the mixture into uniform orientation and polymerizing themixture. The orientation of the film can be planar, i.e. where theliquid crystal molecules are oriented substantially parallel to thelayer, homeotropic (rectangular or perpendicular to the layer) ortilted.

Such optical films are described, for example, in EP 0 940 707 B1, EP 0888 565 B1 and GB 2 329 393 B1.

Current RM coatings require an alignment layer, either rubbed polyimide(PI) or photoalignment layers. Without this alignment layer, there is nopreferential order for the RM monomers to orient themselves. This leadsto random alignment of the RM monomers and upon curing, random alignmentof the polymer.

The standard techniques for giving homogeneous alignment of reactivemesogen molecules have downsides associated with them. The mechanicalrubbing process for rubbed PI alignment can introduce some electrostaticcharge and debris on the RM coatings, which can have a detrimentaleffect on the alignment.

Photoalignment processes have been invented recently which are anon-contact approach, however this adds another coating step into theproduction process which are undesirable from a cost perspective. Forexample, N. A. Clark et al., Langmuir 2010, 26(22), 17482-17488 haveshown that it is possible to self-assemble a compound of the followingstructure

onto a substrate to give a monolayer that is able to be photoaligned toinduce homogeneous alignment of a liquid crystal.

In Situ self-alignment has also been shown to be possible for liquidcrystal systems, like it is disclosed in EP 3 390 570 A1, however neverfor reactive mesogen films.

For non-reactive liquid crystals, an additive containing photoalignmentgroups and photopolymerizable groups are used. In this process, the LCcell is irradiated with polarized UV light while in the isotropic phase.Then when cooled into the nematic phase, the LC adopts the alignmentgiven by the, now reacted, self-alignment additive. This is difficultfor RM films as most of the components in the formulation arephotopolymerizable like the self-aligned additive. If the RM film isirradiated with UV light, the film will simply polymerize in the randomalignment it has when coated so self-alignment additives which work forLC cannot work in RM films.

Therefore, there is still the need for new and preferably improved,method for the preparation of a homogeneous aligned liquid crystalpolymer films or polymer films as such, which do not exhibit thedrawbacks of prior art methods or films or if so, do only exhibit themto a less extent.

Advantageously, such method, should preferably be applicable for thepreparation of uniform aligned polymer films that should be produced bycompatible, cost-efficient and commonly known methods for the massproduction, and the resulting polymer films should exhibit, preferablyat the same time, a favourable adhesion to a substrate, hightransparency to VIS-light, a lower dark state transmittance, afavourable high temperature stability or durability, and in addition, auniform alignment.

Other aims of the present invention are immediately evident to theperson skilled in the art from the following detailed description.

Surprisingly, the inventors of the present invention have found that oneor more, preferably all of the above requirements aims can be achieved,preferably at the same time, by a method for the preparation of ahomogeneous aligned liquid crystal polymer films according to claim 1.

SUMMARY OF THE INVENTION

Thus, the invention relates to a method for manufacturing a homogeneousaligned polymer film comprising at least the steps of:

-   -   providing a polymerizable liquid crystal mixture, comprising one        or more polymerizable liquid crystal molecules, and one or more        self assembling photoalignment agents, on a substrate;    -   irradiating the liquid crystal mixture with linearly polarised        light causing photoalignment of the polymerizable liquid crystal        mixture;    -   optionally curing the polymerizable liquid crystal compounds by        irradiation with ultraviolet light.

The invention further relates to a polymer film obtainable, preferablyobtained, from the method, as described above and below.

The invention further relates to the use of a polymer film, as describedabove and below, in an optical component, to an optical componentcomprising a polymer film in accordance with the present invention andto the use of such optical component in an optical device.

Finally, the present invention relates to an optical device opticalcomprising a polymer film or an optical component in accordance with thepresent invention.

Terms and Definitions

As used herein, the term “polymer” will be understood to mean a moleculethat encompasses a backbone of one or more distinct types of repeatingunits (the smallest constitutional unit of the molecule) and isinclusive of the commonly known terms “oligomer”, “copolymer”,“homopolymer” and the like. Further, it will be understood that the termpolymer is inclusive of, in addition to the polymer itself, residuesfrom initiators, catalysts, and other elements attendant to thesynthesis of such a polymer, where such residues are understood as notbeing covalently incorporated thereto. Further, such residues and otherelements, while normally removed during post polymerisation purificationprocesses, are typically mixed or co-mingled with the polymer such thatthey generally remain with the polymer when it is transferred betweenvessels or between solvents or dispersion media.

The term “(meth)acrylic polymer” as used in the present inventionincludes a polymer obtained from acrylic monomers, a polymer obtainablefrom methacrylic monomers, and a corresponding co-polymer obtainablefrom mixtures of such monomers.

The term “polymerisation” means the chemical process to form a polymerby bonding together multiple polymerisable groups or polymer precursors(polymerisable compounds) containing such polymerisable groups.

The terms “film” and “layer” include rigid or flexible, self-supportingor freestanding films with mechanical stability, as well as coatings orlayers on a supporting substrate or between two substrates.

The term “liquid crystal” or “LC” relates to materials havingliquid-crystalline mesophases in some temperature ranges (thermotropicLCs) or in some concentration ranges in solutions (lyotropic LCs). Theyobligatorily contain mesogenic compounds.

The terms “mesogenic compound” and “liquid crystal compound” mean acompound comprising one or more calamitic (rod- or board/lath-shaped) ordiscotic (disk-shaped) mesogenic groups. The term “mesogenic group”means a group with the ability to induce liquid-crystalline phase (ormesophase) behaviour. The compounds comprising mesogenic groups do notnecessarily have to exhibit a liquid-crystalline mesophase themselves.It is also possible that they show liquid-crystalline mesophases only inmixtures with other compounds, or when the mesogenic compounds ormaterials, or the mixtures thereof, are polymerised. This includeslow-molecular-weight non-reactive liquid-crystalline compounds, reactiveor polymerisable liquid-crystalline compounds, and liquid-crystallinepolymers.

A calamitic mesogenic group is usually comprising a mesogenic coreconsisting of one or more aromatic or non-aromatic cyclic groupsconnected to each other directly or via linkage groups, optionallycomprising terminal groups attached to the ends of the mesogenic core,and optionally comprising one or more lateral groups attached to thelong side of the mesogenic core, wherein these terminal and lateralgroups are usually selected e.g. from carbyl or hydrocarbyl groups,polar groups like halogen, nitro, hydroxy, etc., or polymerisablegroups.

The term “reactive mesogen” means a polymerisable mesogenic or liquidcrystal compound, preferably a monomeric compound. These compounds canbe used as pure compounds or as mixtures of reactive mesogens with othercompounds functioning as photoinitiators, inhibitors, surfactants,stabilizers, chain transfer agents, non-polymerisable compounds, etc.

Polymerisable compounds with one polymerisable group are also referredto as “monoreactive” compounds, compounds with two polymerisable groupsas “direactive” compounds, and compounds with more than twopolymerisable groups as “multireactive” compounds. Compounds without apolymerisable group are also referred to as “non-reactive ornon-polymerisable” compounds.

A photoreactive group according to the present invention is a functionalgroup of a molecule that causes a change of the geometry of the moleculeeither by bond rotation, skeletal rearrangement or atom- orgroup-transfer, or by dimerization, upon irradiation with light of asuitable wavelength that can be absorbed by the molecule.

A photoreactive mesogen according to the present invention is amesogenic compound comprising one or more photoreactive groups.

Examples of photoreactive groups are —C═C— double bonds and azo groups(—N═N—).

Examples of molecular structures and sub-structures comprising suchphotoreactive groups are stilbene, (1,2-difluoro-2 phenylvinyl)-benzene, cinnamate, 4-phenylbut-3-en-2-one, chalcone, coumarin,chromone, pentalenone and azobenzene.

The term “polymerisable liquid crystal mixture” means a material, whichcomprises of more than 90% by weight, preferably more than 95% byweight, more preferably more than 98% by weight of polymerisable liquidcrystal molecule compounds, as described above and below.

The term “non-mesogenic compound or material” means a compound ormaterial that does not contain a mesogenic group as defined above.

Visible light is electromagnetic radiation that has wavelength in arange from about 400 nm to about 740 nm. Ultraviolet (UV) light iselectromagnetic radiation with a wavelength in a range from about 200 nmto about 450 nm.

According to the present application, the term “linearly polarisedlight” means light, which is at least partially linearly polarized.Preferably, the aligning light is linearly polarized with a degree ofpolarization of more than 5:1. Wavelengths, intensity and energy of thelinearly polarised light are chosen depending on the photosensitivity ofthe photoalignable material. Typically, the wavelengths are in the UV-A,UV-B and/or UV-C range or in the visible range. Preferably, the linearlypolarised light comprises light of wavelengths less than 450 nm, morepreferably less than 420 nm at the same time the linearly polarisedlight preferably comprises light of wavelengths longer than 280 nm,preferably more than 320 nm, more preferably over 350 nm.

The Irradiance (E_(e)) or radiation power is defined as the power ofelectromagnetic radiation (dθ) per unit area (dA) incident on a surface:

E_(e) = d θ/dA.

The radiant exposure or radiation dose (H_(e)), is as the irradiance orradiation power (E_(e)) per time (t):

H_(e) = E_(e) ⋅ t.

All temperatures, such as, for example, the melting point T(C,N) orT(C,S), the transition from the smectic (S) to the nematic (N) phaseT(S,N) and the clearing point T(N,I) of the liquid crystals, are quotedin degrees Celsius. All temperature differences are quoted indifferential degrees.

The term “clearing point” means the temperature at which the transitionbetween the mesophase with the highest temperature range and theisotropic phase occurs.

The term “director” is known in prior art and means the preferredorientation direction of the long molecular axes (in case of calamiticcompounds) or short molecular axes (in case of discotic compounds) ofthe liquid-crystalline or RM molecules. In case of uniaxial ordering ofsuch anisotropic molecules, the director is the axis of anisotropy.

The term “alignment” or “orientation” relates to alignment(orientational ordering) of anisotropic units of material such as smallmolecules or fragments of big molecules in a common direction named“alignment direction”. In an aligned layer of liquid-crystalline or RMmaterial the liquid-crystalline director coincides with the alignmentdirection so that the alignment direction corresponds to the directionof the anisotropy axis of the material.

The terms “uniform orientation” or “uniform alignment” of anliquid-crystalline or RM material, for example in a layer of thematerial, mean that the long molecular axes (in case of calamiticcompounds) or the short molecular axes (in case of discotic compounds)of the liquid-crystalline or RM molecules are oriented substantially inthe same direction. In other words, the lines of liquid-crystallinedirector are parallel.

The term “homeotropic structure” or “homeotropic orientation” refers toa film wherein the optical axis is substantially perpendicular to thefilm plane.

The term “planar structure” or “planar orientation” or “homogeneousalignment” refers to a film wherein the optical axis is substantiallyparallel to the film plane.

The term “negative (optical) dispersion” refers to a birefringent orliquid crystalline material or layer that displays reverse birefringencedispersion where the magnitude of the birefringence (Δn) increases withincreasing wavelength (λ). I.e. |Δn (450)|<|Δn (550)|, or Δn (450)/Δn(550)<1, where Δn (450) and Δn (550) are the birefringence of thematerial measured at wavelengths of 450 nm and 550 nm respectively. Incontrast, positive (optical) dispersion” means a material or layerhaving |Δn (450)|>|Δn (550)| or Δn (450)/Δn (550)>1. See also forexample A. Uchiyama, T. Yatabe “Control of Wavelength Dispersion ofBirefringence for Oriented Copolycarbonate Films Containing Positive andNegative Birefringent Units”. J. Appl. Phys. Vol. 42 pp 6941-6945(2003).

Since the optical retardation at a given wavelength is defined as theproduct of birefringence and layer thickness as described above[R(λ)=Δn(λ)·d], the optical dispersion can be expressed either as the“birefringence dispersion” by the ratio Δn(450)/Δn(550), or as“retardation dispersion” by the ratio R(450)/R(550), wherein R(450) andR(550) are the retardation of the material measured at wavelengths of450 nm and 550 nm respectively. Since the layer thickness d does notchange with the wavelength, R (450)/R (550) is equal to Δn (450)/Δn(550). Thus, a material or layer with negative or reverse dispersion hasR (450)/R (550)<1 or |R (450)|<|R (550)|, and a material or layer withpositive or normal dispersion has R (450)/R (550)>1 or |R (450)|>|R(550)|.

In the present invention, unless stated otherwise “optical dispersion”means the retardation dispersion i.e. the ratio R (450)/R (550).

The term “high dispersion” means that the absolute value of thedispersion shows a large deviation from 1, whereas the term “lowdispersion” means that the absolute value of the dispersion shows asmall deviation from 1. Thus “high negative dispersion” means that thedispersion value is significantly smaller than 1, and “low negativedispersion” means that the dispersion value is only slightly smallerthan 1.

The retardation (R(λ)) of a material can be measured using aspectroscopic ellipsometer, for example the M2000 spectroscopicellipsometer manufactured by J. A. Woollam Co., This instrument iscapable of measuring the optical retardance in nanometres of abirefringent sample e.g. Quartz over a range of wavelengths typically,370 nm to 2000 nm. From this data, it is possible to calculate thedispersion (R(450)/R(550) or Δn(450)/Δn(550)) of a material.

A method for carrying out these measurements was presented at theNational Physics Laboratory (London, UK) by N. Singh in October 2006 andentitled “Spectroscopic Ellipsometry, Part 1—Theory and Fundamentals,Part 2—Practical Examples and Part 3—measurements”. In accordance withthe measurement procedures described Retardation Measurement (RetMeas)Manual (2002) and Guide to WVASE (2002) (Woollam Variable AngleSpectroscopic Ellipsometer) published by J. A. Woollam Co. Inc (Lincoln,Nebr., USA). Unless stated otherwise, this method is used to determinethe retardation of the materials, films and devices described in thisinvention.

The term “A plate” refers to an optical retarder utilizing a layer ofuniaxially birefringent material with its extraordinary axis orientedparallel to the plane of the layer.

The term “C plate” refers to an optical retarder utilizing a layer ofuniaxially birefringent material with its extraordinary axis orientedperpendicular to the plane of the layer.

In A/C-plates comprising optically uniaxial birefringent liquid crystalmaterial with uniform orientation, the optical axis of the film is givenby the direction of the extraordinary axis. An A (or C) plate comprisingoptically uniaxial birefringent material with positive birefringence isalso referred to as “positive A (or C) plate” or “+A (or +C) plate”.

An A (or C) plate comprising a film of optically uniaxial birefringentmaterial with negative birefringence, such as discotic anisotropicmaterials is also referred to as “negative A (or C) plate” or “−A (or C)plate” depending on the orientation of the discotic materials. A filmmade from a cholesteric calamitic material with a reflection band in theUV part of the spectrum also has the optics of a negative C plate.

The birefringence Δn is defined as follows

Δ n = n_(e) − n_(o)wherein n_(e) is the extraordinary refractive index and n_(o) is theordinary refractive index, and the average refractive index n_(av.) isgiven by the following equation:

n_(av.) = ((2n_(o)² + n_(e)²)/3)^(1/2)

The average refractive index n_(av.) and the ordinary refractive indexn_(o) can be measured using an Abbe refractometer. Δn can then becalculated from the above equations.

Unless the context clearly indicates otherwise, as used herein pluralforms of the terms herein are to be construed as including the singularform and vice versa.

All physical properties have been and are determined according to “MerckLiquid Crystals, Physical Properties of Liquid Crystals”, StatusNovember 1997, Merck KGaA, Germany and are given for a temperature of20° C., unless explicitly stated otherwise. The optical anisotropy (Δn)is determined at a wavelength of 589.3 nm

In case of doubt the definitions as given in C. Tschierske, G. Pelzl andS. Diele, Angew. Chem. 2004, 116, 6340-6368 shall apply.

Unless explicitly stated otherwise in the given generic formulae, thefollowing terms have the following meanings:

The term “organic group” denotes a carbon or hydrocarbon group.

The term “carbon group” denotes a mono- or polyvalent organic groupcontaining at least one carbon atom, where this either contains nofurther atoms (such as, for example, —C≡C—) or optionally contains oneor more further atoms, such as, for example, N, O, S, P, Si, Se, As, Teor Ge (for example carbonyl, etc.). The term “hydrocarbon group” denotesa carbon group which additionally contains one or more H atoms andoptionally one or more heteroatoms, such as, for example, N, O, S, P,Si, Se, As, Te or Ge.

“Halogen” denotes F, Cl, Br or I.

A carbon or hydrocarbon group can be a saturated or unsaturated group.Unsaturated groups are, for example, aryl, alkenyl or alkynyl groups. Acarbon or hydrocarbon radical having 3 or more atoms can bestraight-chain, branched and/or cyclic and may also contain spiro linksor condensed rings.

The terms “alkyl”, “aryl”, “heteroaryl”, etc., also encompass polyvalentgroups, for example alkylene, arylene, heteroarylene, etc.

The term “aryl” denotes an aromatic carbon group or a group derivedtherefrom. The term “heteroaryl” denotes “aryl” as defined above,containing one or more heteroatoms.

Preferred carbon and hydrocarbon groups are optionally substitutedalkyl, alkenyl, alkynyl, alkoxy, alkylcarbonyl, alkoxycarbonyl,alkylcarbonyloxy and alkoxycarbonyloxy having 1 to 40, preferably 1 to25, particularly preferably 1 to 18, C atoms, optionally substitutedaryl or aryloxy having 6 to 40, preferably 6 to 25, C atoms, oroptionally substituted alkylaryl, arylalkyl, alkylaryloxy, arylalkyloxy,arylcarbonyl, aryloxycarbonyl, arylcarbonyloxy and aryloxycarbonyloxyhaving 6 to 40, preferably 6 to 25, C atoms.

Further preferred carbon and hydrocarbon groups are C₁-C₄₀ alkyl, C₂-C₄₀alkenyl, C₂-C₄₀ alkynyl, C₃-C₄₀ allyl, C₄-C₄₀ alkyldienyl, C₄-C₄₀polyenyl, C₆-C₄₀ aryl, C₆-C₄₀ alkylaryl, C₆-C₄₀ arylalkyl, C₆-C₄₀alkylaryloxy, C₆-C₄₀ arylalkyloxy, C₂-C₄₀ heteroaryl, C₄-C₄₀ cycloalkyl,C₄-C₄₀ cycloalkenyl, etc. Particular preference is given to C₁-C₂₂alkyl, C₂-C₂₂ alkenyl, C₂-C₂₂ alkynyl, C₃-C₂₂ allyl, C₄-C₂₂ alkyldienyl,C₆-C₁₂ aryl, C₆-C₂₀ arylalkyl and C₂-C₂₀ heteroaryl.

Further preferred carbon and hydrocarbon groups are straight-chain,branched or cyclic alkyl radicals having 1 to 40, preferably 1 to 25, Catoms, which are unsubstituted or mono- or polysubstituted by F, Cl, Br,I or CN and in which one more non-adjacent CH₂ groups may each bereplaced, independently of one another, by —C(R^(z))═C(R^(z))—, —C≡C—,—N(R^(z))—, —O—, —S—, —CO—, —CO—O—, —O—CO—, —O—CO—O— in such a way thatO and/or S atoms are not linked directly to one another.

R^(z) preferably denotes H, halogen, a straight-chain, branched orcyclic alkyl chain having 1 to 25 C atoms, in which, in addition, one ormore non-adjacent C atoms may be replaced by —O—, —S—, —CO—, —CO—O—,—O—CO— or —O—CO—O— and in which one or more H atoms may be replaced byfluorine, an optionally substituted aryl or aryloxy group having 6 to 40C atoms, or an optionally substituted heteroaryl or heteroaryloxy grouphaving 2 to 40 C atoms.

Preferred alkyl groups are, for example, methyl, ethyl, n-propyl,isopropyl, n-butyl, isobutyl, s-butyl, t-butyl, 2-methylbutyl, n-pentyl,s-pentyl, cyclopentyl, n-hexyl, cyclohexyl, 2-ethylhexyl, n-heptyl,cycloheptyl, n-octyl, cyclooctyl, n-nonyl, n-decyl, n-undecyl,n-dodecyl, trifluoromethyl, perfluoro-n-butyl, 2,2,2-trifluoroethyl,perfluorooctyl and perfluorohexyl.

Preferred alkenyl groups are, for example, ethenyl, propenyl, butenyl,pentenyl, cyclopentenyl, hexenyl, cyclohexenyl, heptenyl, cycloheptenyl,octenyl and cyclooctenyl.

Preferred alkynyl groups are, for example, ethynyl, propynyl, butynyl,pentynyl, hexynyl and octynyl.

Preferred alkoxy groups are, for example, methoxy, ethoxy,2-methoxy-ethoxy, n-propoxy, i-propoxy, n-butoxy, i-butoxy, s-butoxy,t-butoxy, 2-methylbutoxy, n-pentoxy, n-hexoxy, n-heptoxy, n-octoxy,n-nonoxy, n-decoxy, n-undecoxy and n-dodecoxy.

Preferred amino groups are, for example, dimethylamino, methylamino,methylphenylamino and phenylamino.

Aryl and heteroaryl groups can be monocyclic or polycyclic, i.e. theycan contain one ring (such as, for example, phenyl) or two or morerings, which may also be fused (such as, for example, naphthyl) orcovalently bonded (such as, for example, biphenyl), or contain acombination of fused and linked rings. Heteroaryl groups contain one ormore heteroatoms, preferably selected from O, N, S and Se. A ring systemof this type may also contain individual non-conjugated units, as is thecase, for example, in the fluorene basic structure.

Particular preference is given to mono-, bi- or tricyclic aryl groupshaving 6 to 25 C atoms and mono-, bi- or tricyclic heteroaryl groupshaving 2 to 25 C atoms, which optionally contain fused rings and areoptionally substituted. Preference is furthermore given to 5-, 6- or7-membered aryl and heteroaryl groups, in which, in addition, one ormore CH groups may be replaced by N, S or O in such a way that O atomsand/or S atoms are not linked directly to one another.

Preferred aryl groups are derived, for example, from the parentstructures benzene, biphenyl, terphenyl, [1,1′:3′,1″]terphenyl,naphthalene, anthracene, binaphthyl, phenanthrene, pyrene,dihydropyrene, chrysene, perylene, tetracene, pentacene, benzopyrene,fluorene, indene, indenofluorene, spirobifluorene, etc.

Preferred heteroaryl groups are, for example, 5-membered rings, such aspyrrole, pyrazole, imidazole, 1,2,3-triazole, 1,2,4-triazole, tetrazole,furan, thiophene, selenophene, oxazole, isoxazole, 1,2-thiazole,1,3-thiazole, 1,2,3-oxadiazole, 1,2,4-oxadiazole, 1,2,5-oxadiazole,1,3,4-oxadiazole, 1,2,3-thiadiazole, 1,2,4-thiadiazole,1,2,5-thiadiazole, 1,3,4-thiadiazole, 6-membered rings, such aspyridine, pyridazine, pyrimidine, pyrazine, 1,3,5-triazine,1,2,4-triazine, 1,2,3-triazine, 1,2,4,5-tetrazine, 1,2,3,4-tetrazine,1,2,3,5-tetrazine, or condensed groups, such as indole, isoindole,indolizine, indazole, benzimidazole, benzotriazole, purine,naphthimidazole, phenanthrimidazole, pyridimidazole, pyrazinimidazole,quinoxalinimidazole, benzoxazole, naphthoxazole, anthroxazole,phen-anthroxazole, isoxazole, benzothiazole, benzofuran, isobenzofuran,dibenzofuran, quinoline, isoquinoline, pteridine, benzo-5,6-quinoline,benzo-6,7-quinoline, benzo-7,8-quinoline, benzoisoquinoline, acridine,phenothiazine, phenoxazine, benzopyridazine, benzopyrimidine,quinoxaline, phenazine, naphthyridine, azacarbazole, benzocarboline,phenanthridine, phenanthroline, thieno[2,3b]thiophene,thieno[3,2b]thiophene, dithienothiophene, dihydrothieno[3,4-b]-1,4-dioxin, isobenzothiophene, dibenzothiophene,benzothiadiazothiophene, or combinations of these groups. The heteroarylgroups may also be substituted by alkyl, alkoxy, thioalkyl, fluorine,fluoroalkyl or further aryl or heteroaryl groups.

The (non-aromatic) alicyclic and heterocyclic groups encompass bothsaturated rings, i.e. those containing exclusively single bonds, andalso partially unsaturated rings, i.e. those which may also containmultiple bonds. Heterocyclic rings contain one or more heteroatoms,preferably selected from Si, O, N, S and Se.

The (non-aromatic) alicyclic and heterocyclic groups can be monocyclic,i.e. contain only one ring (such as, for example, cyclohexane), orpolycyclic, i.e. contain a plurality of rings (such as, for example,decahydronaphthalene or bicyclooctane). Particular preference is givento saturated groups. Preference is furthermore given to mono-, bi- ortricyclic groups having 3 to 25 C atoms, which optionally contain fusedrings and are optionally substituted. Preference is furthermore given to5-, 6-, 7- or 8-membered carbocyclic groups, in which, in addition, oneor more C atoms may be replaced by Si and/or one or more CH groups maybe replaced by N and/or one or more non-adjacent CH₂ groups may bereplaced by —O— and/or —S—.

Preferred alicyclic and heterocyclic groups are, for example, 5-memberedgroups, such as cyclopentane, tetrahydrofuran, tetrahydrothiofuran,pyrrolidine, 6-membered groups, such as cyclohexane, silinane,cyclohexene, tetrahydropyran, tetrahydrothiopyran, 1,3-dioxane,1,3-dithiane, piperidine, 7-membered groups, such as cycloheptane, andfused groups, such as tetrahydronaphthalene, decahydronaphthalene,indane, bicyclo[1.1.1]-pentane-1,3-diyl, bicyclo[2.2.2]octane-1,4-diyl,spiro[3.3]heptane-2,6-diyl, octahydro-4,7-methanoindane-2,5-diyl.

The aryl, heteroaryl, carbon and hydrocarbon radicals optionally haveone or more substituents, which are preferably selected from the groupcomprising silyl, sulfo, sulfonyl, formyl, amine, imine, nitrile,mercapto, nitro, halogen, C₁₋₁₂ alkyl, C₆₋₁₂ aryl, C₁₋₁₂ alkoxy,hydroxyl, or combinations of these groups.

Preferred substituents are, for example, solubility-promoting groups,such as alkyl or alkoxy, and electron-withdrawing groups, such asfluorine, nitro or nitrile.

Preferred substituents, unless stated otherwise, also referred to as “L”above and below, are F, Cl, Br, I, —CN, —NO₂, —NCO, —NCS, —OCN, —SCN,—C(═O)N(R^(z))₂, —C(═O)Y¹, —C(═O)R^(z), —N(R^(z))₂, in which R^(z) hasthe meaning indicated above, and Y¹ denotes halogen, optionallysubstituted silyl or aryl having 6 to 40, preferably 6 to 20, C atoms,and straight-chain or branched alkyl, alkoxy, alkylcarbonyl,alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy having 1 to 25 Catoms, preferably 2 to 12, in which one or more H atoms may optionallybe replaced by F or Cl.

“Substituted silyl or aryl” preferably means substituted by halogen,—CN, R^(y1), —OR^(y1), —CO—R^(y1), —CO—O—R^(y1), —O—CO—R^(y1) or—O—CO—O—R^(y1), in which R^(y1) has the meaning indicated above.

Particularly preferred substituents L are, for example, F, Cl, CN, CH₃,C₂H₅, —CH(CH₃)₂, OCH₃, OC₂H₅, CF₃, OCF₃, OCHF₂, OC₂F₅, furthermorephenyl.

Above and below “halogen” denotes F, Cl, Br or I.

Above and below, the terms “alkyl”, “aryl”, “heteroaryl”, etc., alsoencompass polyvalent groups, for example alkylene, arylene,heteroarylene, etc.

In the formula shown above and below, a substituted phenylene ring

is preferably

in which L has, on each occurrence identically or differently, one ofthe meanings given above and below, and is preferably F, Cl, CN, NO₂,CH₃, C₂H₅, C(CH₃)₃, CH(CH₃)₂, CH₂CH(CH₃)C₂H₅, OCH₃, CO₂H₅, COCH₃,COC₂H₅, COOCH₃, COOC₂H₅, CF₃, OCF₃, OCHF₂, CO₂F₅ or P-Sp-, verypreferably F, Cl, CN, CH₃, C₂H₅, OCH₃, COCH₃, OCF₃ or P-Sp-, mostpreferably F, Cl, CH₃, OCH₃, COCH₃ or OCF₃.

“Halogen” denotes F, Cl, Br or I, preferably F or Cl, more preferably F.

“Polymerisable groups” (P) are preferably selected from groupscontaining a C═C double bond or C≡C triple bond, and groups which aresuitable for polymerisation with ring opening, such as, for example,oxetane or epoxide groups.

Preferably, polymerisable groups (P) are selected from the groupconsisting of CH₂═CW¹—COO—, CH₂═CW¹—CO—,

CH₂═CW²—(O)_(k3)—, CW¹═CH—CO—(O)_(k3)—, CW¹═CH—CO—NH—, CH₂═CW¹—CO—NH—,CH₃—CH═CH—O—, (CH₂═CH)₂CH—OCO—, (CH₂═CH—CH₂)₂CH—OCO—, (CH₂═CH)₂CH—O—,(CH₂═CH—CH₂)₂N—, (CH₂═CH—CH₂)₂N—CO—, CH₂═CW¹—CO—NH—,CH₂═CH—(COO)_(k1)-Phe-(O)_(k2)—, CH₂═CH—(CO)_(k1)-Phe-(O)_(k2)—,Phe-CH═CH—,in which

W¹ denotes H, F, Cl, CN, CF₃, phenyl or alkyl having 1 to 5 C atoms, inparticular H, F, Cl or CH₃,

W² denotes H or alkyl having 1 to 5 C atoms, in particular H, methyl,ethyl or n-propyl,

W³ and W⁴ each, independently of one another, denote H, Cl or alkylhaving 1 to 5 C atoms, Phe denotes 1,4-phenylene, which is optionallysubstituted by one or more radicals L as being defined above but beingdifferent from P-Sp, preferably preferred substituents L are F, Cl, CN,NO₂, CH₃, C₂H₅, OCH₃, CO₂H₅, COCH₃, COC₂H₅, COOCH₃, COOC₂H₅, CF₃, OCF₃,OCHF₂, CO₂F₅, furthermore phenyl, and

k₁, k₂ and k₃ each, independently of one another, denote 0 or 1, k₃preferably denotes 1, and k₄ is an integer from 1 to 10.

Particularly preferred polymerizable groups P are CH₂═CH—COO—,CH₂═C(CH₃)—COO—, CH₂═CF—COO—, CH₂═CH—, CH₂═CH—O—, (CH₂═CH)₂CH—OCO—,(CH₂═CH)₂CH—O—,

in which W² denotes H or alkyl having 1 to 5 C atoms, in particular H,methyl, ethyl or n-propyl,

Further preferred polymerizable groups (P) are vinyloxy, acrylate,methacrylate, fluoroacrylate, chloroacrylate, oxetane and epoxide, mostpreferably acrylate or methacrylate, in particular acrylate.

Preferably, all multireactive polymerisable compounds and sub-formulaethereof contain instead of one or more radicals P-Sp-, one or morebranched radicals containing two or more polymerisable groups P(multireactive polymerisable radicals).

Suitable radicals of this type, and polymerisable compounds containingthem, are described, for example, in U.S. Pat. No. 7,060,200 B1 or US2006/0172090 A1.

Particular preference is given to multireactive polymerisable radicalsselected from the following formulae:—X-alkyl-CHP^(x)—CH₂—CH₂P^(y)  I*a—X-alkyl-C(CH₂P^(x))(CH₂P^(y))—CH₂P^(z)  I*b—X-alkyl-CHP^(x)CHP^(y)—CH₂P^(z)  I*c—X-alkyl-C(CH₂P^(x))(CH₂P^(y))—C_(aa)H_(2aa+1)  I*d—X-alkyl-CHP^(x)—CH₂P^(y)  I*e—X-alkyl-CHP^(x)P^(y)  I*f—X-alkyl-CP^(x)P^(y)—C_(aa)H_(2aa+1)  I*g—X-alkyl-C(CH₂P^(v))(CH₂P^(w))—CH₂OCH₂—C(CH₂P^(x))(CH₂P^(y))CH₂P^(z)  I*h—X-alkyl-CH((CH₂)_(aa)P^(x))((CH₂)_(bb)P^(y))  I*i—X-alkyl-CHP^(x)CHP^(y)—C_(aa)H_(2aa+1)  I*kin which

-   alkyl denotes a single bond or straight-chain or branched alkylene    having 1 to 12 C atoms, in which one or more non-adjacent CH₂ groups    may each be replaced, independently of one another,    -   by —C(R^(x))═C(R^(x))—, —C≡C—, —N(R^(x))—, —O—, —S—, —CO—,        —CO—O—, —O—CO—, —O—CO—O— in such a way that O and/or S atoms are        not linked directly to one another, and in which, in addition,        one or more H atoms may be replaced by F, Cl or CN, where R^(x)        has one the above-mentioned meaning,-   _(aa) and _(bb) each, independently of one another, denote 0, 1, 2,    3, 4, 5 or 6,-   X has one of the meanings indicated for X′, and-   P^(v) to P^(z) each, independently of one another, have one of the    meanings indicated above for P.

Preferred spacer groups Sp are selected from the formula Sp′—X′, so thatthe radical “P-Sp-” conforms to the formula “P-Sp′—X′—”, where

-   Sp′ denotes alkylene having 1 to 20, preferably 1 to 12 C atoms,    which is optionally mono- or polysubstituted by F, Cl, Br, I or CN    and in which, in addition, one or more non-adjacent CH₂ groups may    each be replaced, independently of one another,    -   by —O—, —S—, —NH—, —NR^(xx)—, —SiR^(xx)R^(yy)—, —CO—, —COO—,        —OCO—, —OCO—O—, —S—CO—, —CO—S—, —NR^(xx)—CO—O—, —O—CO—NR^(0xx)—,        —NR^(xx)—CO—NR^(yy)—, —CH═CH— or —C≡C— in such a way that O        and/or S atoms are not linked directly to one another,-   X′    -   denotes —O—, —S—, —CO—, —COO—, —OCO—, —O—COO—, —CO—NR^(xx)—,        —NR^(xx)—COO—, —NR^(xx)—CO—NR^(yy)—, —OCH₂—, —CH₂O—, —SCH₂—,        —CH₂S—, —CF₂O—, —OCF₂—, —CF₂S—, —SCF₂—, —CF₂CH₂—, —CH₂CF₂—,        —CF₂CF₂—, —CH═N—, —N═CH—, —N═N—, —CH═CR^(xx)—,        —CY^(xx)═CY^(xx)—, —C≡C—, —CH═CH—COO—, —OCO—CH═CH— or a single        bond,-   R^(xx) and R^(yy) each, independently of one another, denote H or    alkyl having 1 to 12 C atoms, and-   Y^(xx) and Y^(yy) each, independently of one another, denote H, F,    Cl or CN.-   X′ is preferably —O—, —S— —CO—, —COO—, —OCO—, —O—COO—, —CO—NR^(xx)—,    —NR^(xx)—CO—, —NR^(xx)—CO—NR^(yy)— or a single bond.

Typical spacer groups Sp′ are, for example, —(CH₂)_(p1)—,—(CH₂CH₂O)_(q1)—CH₂CH₂—, —CH₂CH₂—S—CH₂CH₂—, —CH₂CH₂—NH—CH₂CH₂— or—(SiR^(xx)R^(yy)—O)_(p1)—, in which p1 is an integer from 1 to 12, q1 isan integer from 1 to 3, and R^(xx) and R^(yy) have the above-mentionedmeanings.

Particularly preferred groups —X′—Sp′- are —(CH₂)_(p1)—, —O—(CH₂)_(p1)—,—OCO—(CH₂)_(p1)—, —OCOO—(CH₂)_(p1)—, in which p1 is an integer from 1 to12.

Particularly preferred groups Sp′ are, for example, in each casestraight-chain, methylene, ethylene, propylene, butylene, pentylene,hexylene, heptylene, octylene, nonylene, decylene, undecylene,dodecylene, octadecylene, ethyleneoxyethylene, methyleneoxybutylene,ethylenethioethylene, ethylene-N-methyliminoethylene, 1-methylalkylene,ethenylene, propenylene and butenylene.

For the present invention,

denote 1,4-cyclohexylene, preferably trans-1,4-cyclohexylene, and

denote 1,4-phenylene.

For the present invention the groups —CO—O—, —COO—, —C(═O)O— or—CO₂-denote an ester group of formula

and the groups —O—CO—, —OCO—, —OC(═O)—, —O₂C— or —OOC— denote an estergroup of formula

A “polymer network” is a network in which all polymer chains areinterconnected to form a single macroscopic entity by many crosslinks.

The polymer network can occur in the following types:

-   -   A graft polymer molecule is a branched polymer molecule in which        one or more the side chains are different, structurally or        configurationally, from the main chain.    -   A star polymer molecule is a branched polymer molecule in which        a single branch point gives rise to multiple linear chains or        arms. If the arms are identical, the star polymer molecule is        said to be regular. If adjacent arms are composed of different        repeating subunits, the star polymer molecule is said to be        variegated.    -   A comb polymer molecule consists of a main chain with two or        more three-way branch points and linear side chains. If the arms        are identical the comb polymer molecule is said to be regular.    -   A brush polymer molecule consists of a main chain with linear,        unbranched side chains and where one or more of the branch        points has four-way functionality or larger.

Throughout the description and claims of this specification, the words“comprise” and “contain” and variations of the words, for example“comprising” and “comprises”, mean “including but not limited to”, andare not intended to (and do not) exclude other components. On the otherhand, the word “comprise” also encompasses the term “consisting of” butis not limited to it.

Throughout the description and claims of this specification, the words“obtainable” and “obtained” and variations of the words, mean “includingbut not limited to”, and are not intended to (and do not) exclude othercomponents. On the other hand, the word “obtainable” also encompassesthe term “obtained” but is not limited to it.

All concentrations are quoted in percent by weight and relate to therespective mixture as a whole, all temperatures are quoted in degreesCelsius and all temperature differences are quoted in differentialdegrees.

DETAILED DESCRIPTION

As already mentioned the present invention relates to a method formanufacturing of a homogeneous aligned polymer film comprising at leastthe steps of:

-   -   providing a polymerizable liquid crystal mixture, comprising one        or more polymerizable liquid crystal molecules, and one or more        self assembling photoalignment agents, on a substrate;    -   irradiating the liquid crystal mixture with linearly polarised        light causing photoalignment of the polymerizable liquid crystal        mixture;    -   optionally curing the polymerizable liquid crystal compounds by        irradiation with ultraviolet light.

A self assembling photoalignment agent (SAPA) according to the presentinvention is preferably a compound comprising at least one polar lateralgroup and at least one photoreactive group. Considering theinvestigations for this invention it appears that the polar lateralgroup interacts with the substrate surface thus enabling the SAPA tophase separate from the LC mixture after filling of the LC cell.According to this opinion, the SAPA forms a layer on the substrate whichcan be photoaligned with linearly polarised UV light. The liquid crystalfollows the orientation of the aligned SAPA to give uniform planaralignment across the whole display.

The photoalignment process according to the present invention causes theSAPA to undergo an isomerisation under irradiation with linearlypolarised light of appropriate wavelength. The photoisomerisation is anangle-dependent process, resulting eventually in the photoselection ofSAPA orientations that are preferentially perpendicular to thepolarization of the actinic light and with orientational anisotropycapable of aligning LCs.

The wavelength region of the polarised light is preferably chosen so asto match the absorption spectrum of the SAPA.

Preferably one or more self assembling agents are selected fromcompounds of formula S,

wherein

-   L^(s) each, identically or differently, denote on each occurrence,    identically or differently, denotes F, Cl, CN, SCN, SF₅ or    straight-chain or branched, in each case optionally fluorinated,    alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or    alkoxycarbonyloxy having up to 12 C atoms, (Sp^(s))_(r1)-G, Y, or    (Sp^(s))_(r1)—P^(s),-   P^(s) each, independently of one another, denote a polymerisable    group,-   Sp^(s) on each occurrence, identically or differently, denote a    spacer group,-   Y denotes (R^(b))₂N— or, R^(c)C(O)O—,-   G denotes —OH or Si(OR^(a))₃-   R^(a), R^(b), R^(c) each denote, identically or differently, H,    straight chain or branched alkyl with 1 to 6 C atoms,-   r1 denotes 0 or 1,-   t1, t2 denotes each and independently, 1, 2, 3, 4 or 5, and-   Z^(s) denotes a group selected from —N═N—, —CH═CH—, —CH═CH—COO—,    —OCO—CH═—CH—, —CO—CH═CH—, —CH═CH—CO—, wherein one or more H maybe    replaced by halogen.

Preferred self assembling agents are selected from compounds of formulaS that can be reactive, thus compounds of formula S wherein one or moreof L^(s) are selected from (Sp^(s))_(r1)—P^(s), or non-reactive, thuscompounds thus compounds of formula S wherein none of L^(s) are selectedfrom (Sp^(s))_(r1)—P^(s).

If reactive self assembling agents are chosen, they are selected fromcompounds wherein the photoreaction takes place at another wavelengthsthan the polymerization.

Further preferred self assembling agents are selected from compounds offormula S1

wherein

-   Y denotes (R^(b))₂N—, R^(c)C(O)O—, or a group L^(s),-   Sp denotes a spacer group,-   G denotes —OH or Si(OR^(a))₃-   R^(a), R^(b), R^(c) each denote, identically or differently,    straight chain or branched alkyl with 1 to 6 C atoms,-   L^(s) each, identically or differently, denote a group as defined    for formula S-   t1, t2 denotes 0, 1, 2, 3 or 4,

Preferred compounds of formula S1 are selected from the compounds offormula S1-1 or S1-2

wherein the parameters have the meaning defined above and X^(s) denotesO, —C(O)O—, C(O)NH— or a single bond.

Particularly preferred compounds of formula S-1 are the followingcompounds S1-1 and S1-2,

wherein the parameters have the meaning given above and preferably R^(a)denotes methyl or ethyl, R^(b) and R^(c) denote methyl and n1 denotes aninteger from 0 to 10, preferably 1 to 4.

Preferably the proportion of SAPA preferably of compounds of formula Sin the polymerizable liquid crystal in the LC medium is from 1 to 15%,very preferably from 3 to 12%, in particular 5 to 10%.

The compounds of the formula S and sub-formulae thereof can be pre-paredanalogously to processes known to the person skilled in the art anddescribed in standard works of organic chemistry, such as, for example,in Houben-Weyl, Methoden der organischen Chemie [Methods of OrganicChemistry], Thieme-Verlag, Stuttgart. Some of the compounds are alsocommercially available such as commonly known Methyl Red.

In a preferred embodiment, one or more polymerizable liquid crystals orpolymerizable liquid crystal molecules are selected from compounds offormula P,P^(a)-(Sp^(a))_(s1)-A²-(Z¹-A¹)_(n2)-R^(a)  Pwherein

-   P^(a) each, independently of one another, denote a polymerisable    group,-   Sp^(a) on each occurrence, identically or differently, denote a    spacer group,-   s1 denotes 0 or 1,-   R^(a) denotes F, Cl, CN, SCN, SF₅ or straight-chain or branched, in    each case optionally fluorinated, alkyl, alkoxy, alkylcarbonyl,    alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy having up to    12 C atoms, or P^(a)—(Sp^(a))_(s1)-   A¹, A² each, independently of one another, denote a radical selected    from the following groups:    -   a) the group consisting of trans-1,4-cyclohexylene,        1,4-cyclohexenylene and 4,4′-bicyclohexylene, wherein, in        addition, one or more non-adjacent CH₂ groups may be replaced by        —O— and/or —S— and wherein, in addition, one or more H atoms may        be replaced by F,    -   b) the group consisting of 1,4-phenylene and 1,3-phenylene,        wherein, in addition, one or two CH groups may be replaced by N        and wherein, in addition, one or more H atoms may be replaced by        L,    -   c) the group consisting of tetrahydropyran-2,5-diyl,        1,3-dioxane-2,5-diyl, tetrahydrofuran-2,5-diyl,        cyclobutane-1,3-diyl, piperidine-1,4-diyl, thiophene-2,5-diyl        and selenophene-2,5-diyl, each of which may also be mono- or        polysubstituted by L,    -   d) the group consisting of saturated, partially unsaturated or        fully unsaturated, and optionally substituted, polycyclic        radicals having 5 to 20 cyclic C atoms, one or more of which        may, in addition, be replaced by heteroatoms, preferably        selected from:

-   -   where, in addition, one or more H atoms in these radicals may be        replaced by L, and/or one or more double bonds may be replaced        by single bonds, and/or one or more CH groups may be replaced by        N,

-   n2 denotes 0, 1, 2 or 3,

-   Z¹ denotes, in case of multiple occurrence independently of one    another, —O—, —S—, —CO—, —COO—, —OCO—, —S—CO—, —CO—S—, —O—COO—,    —CO—NR⁰⁰—, —NR⁰⁰—CO—, —NR⁰⁰—CO—NR⁰⁰⁰, —NR⁰⁰—CO—O—, —O—CO—NR⁰⁰—,    —OCH₂—, —CH₂O—, —SCH₂—, —CH₂S—, —CF₂O—, —OCF₂—, —CF₂S—, —SCF₂—,    —CH₂CH₂—, —(CH₂)_(n1), —CF₂CH₂—, —CH₂CF₂—, —CF₂CF₂—, —CH═N—, —N═CH—,    —N═N—, —CH═CR⁰⁰—, —CY¹═CY²—, —C≡C—, —CH═CH—COO—, —OCO—CH═CH— or a    single bond,

-   L is P-Sp-, F, Cl, Br, I, —CN, —NO₂, —NCO, —NCS, —OCN, —SCN,    —C(═O)NR⁰⁰R⁰⁰⁰, —C(═O)OR⁰⁰, —C(═O)R⁰⁰, —NR⁰⁰R⁰⁰⁰, —OH, —SF₅,    optionally substituted silyl, aryl or heteroaryl with 1 to 12 C    atoms, straight chain or branched alkyl, alkoxy, alkylcarbonyl,    alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy with 1 to 12,    C atoms, wherein one or more H atoms are optionally replaced by F or    Cl,

-   R⁰, R⁰⁰, R⁰⁰⁰ each, independently of one another, denote H, F or    straight-chain or branched alkyl having 1 to 12 C atoms, wherein, in    addition, one or more H atoms may be replaced by F,

-   Y¹ and Y² independently of each other denote H, F, Cl or CN,

-   n is 1, 2, 3 or 4,

-   n1 is an integer from 1 to 10.

-   M denotes —O—, —S—, —CH₂—, —CHY¹— or —CY¹Y²—, and

-   Y¹ and Y² each, independently of one another, have one of the    meanings indicated above for R^(o) or denote Cl or CN.

Preferred compounds formula P are selected from compounds that can bemono-, di- or multireactive.

Preferably, one or more polymerizable liquid crystal molecules areselected from one or more di- or multireactive mesogenic compounds areselected of formula DRMP¹-Sp¹-MG-Sp²-P²  DRMwherein

-   P¹ and P² independently of each other denote a polymerisable group,-   Sp¹ and Sp² independently of each other are a spacer group or a    single bond, and-   MG is a rod-shaped mesogenic group, which is preferably selected of    formula MG    -(A¹¹-Z¹¹)_(n)-A¹²-  MG    wherein-   A¹¹ and A¹² denote, in case of multiple occurrence independently of    one another, an aromatic or alicyclic group, which optionally    contains one or more heteroatoms selected from N, O and S, and is    optionally mono- or polysubstituted by L¹¹,-   L¹¹ is P-Sp-, F, Cl, Br, I, —CN, —NO₂, —NCO, —NCS, —OCN, —SCN,    —C(═O)NR⁰⁰R⁰⁰⁰, —C(═O)OR⁰⁰, —C(═O)R⁰⁰, —NR⁰⁰R⁰⁰⁰, —OH, —SF₅,    optionally substituted silyl, aryl or heteroaryl with 1 to 12,    preferably 1 to 6 C atoms, and straight chain or branched alkyl,    alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or    alkoxycarbonyloxy with 1 to 12, preferably 1 to 6 C atoms, wherein    one or more H atoms are optionally replaced by F or Cl,-   R⁰⁰ and R⁰⁰⁰ each, independently of one another, denote H, F or    straight-chain or branched alkyl having 1 to 12 C atoms, wherein, in    addition, one or more H atoms may be replaced by F,-   Z¹¹ denotes, in case of multiple occurrence independently of one    another, —O—, —S—, —CO—, —COO—, —OCO—, —S—CO—, —CO—S—, —O—COO—,    —CO—NR⁰⁰—, —NR⁰⁰—CO—, —NR⁰⁰—CO—NR⁰⁰⁰, —NR⁰⁰—CO—O—, —O—CO—NR⁰⁰—,    —OCH₂—, —CH₂O—, —SCH₂—, —CH₂S—, —CF₂O—, —OCF₂—, —CF₂S—, —SCF₂—,    —CH₂CH₂—, —(CH₂)_(n1), —CF₂CH₂—, —CH₂CF₂—, —CF₂CF₂—, —CH═N—, —N═CH—,    —N═N—, —CH═CR⁰⁰—, —CY¹═CY²—, —C≡C—, —CH═CH—COO—, —OCO—CH═CH— or a    single bond,-   Y¹ and Y² independently of each other denote H, F, Cl or CN,-   n is 1, 2, 3 or 4, preferably 1 or 2, most preferably 2,-   n1 is an integer from 1 to 10, preferably 1, 2, 3 or 4.

Preferred groups A¹¹ and A¹² include, without limitation, furan, pyrrol,thiophene, oxazole, thiazole, thiadiazole, imidazole, phenylene,cyclohexylene, bicyclooctylene, cyclohexenylene, pyridine, pyrimidine,pyrazine, azulene, indane, fluorene, naphthalene, tetrahydronaphthalene,anthracene, phenanthrene and dithienothiophene, all of which areunsubstituted or substituted by 1, 2, 3 or 4 groups L¹¹ as definedabove.

Particular preferred groups A¹¹ and A¹² are selected from 1,4-phenylene,pyridine-2,5-diyl, pyrimidine-2,5-diyl, thiophene-2,5-diyl,naphthalene-2,6-diyl, 1,2,3,4-tetrahydro-naphthalene-2,6-diyl,indane-2,5-diyl, bicyclooctylene or 1,4-cyclohexylene wherein one or twonon-adjacent CH₂ groups are optionally replaced by O and/or S, whereinthese groups are unsubstituted or substituted by 1, 2, 3 or 4 groups Las defined above.

Particular preferred groups Z¹¹ are in each occurrence independentlyfrom another preferably selected from —COO—, —OCO—, —CH₂CH₂—, —CF₂O—,—OCF₂—, —C≡C—, —CH═CH—, —OCO—CH═CH—, —CH═CH—COO—, or a single bond,

Very preferred one or more polymerizable liquid crystal molecules areselected from direactive mesogenic compounds of formula DRM are selectedfrom the following formulae:

wherein

-   P⁰ is, in case of multiple occurrence independently of one another,    a polymerisable group, preferably an acryl, methacryl, oxetane,    epoxy, vinyl, heptadiene, vinyloxy, propenyl ether or styrene group,-   L has on each occurrence identically or differently one of the    meanings given for L¹ in formula DRM, and is preferably, in case of    multiple occurrence independently of one another, selected from F,    Cl, CN or optionally halogenated alkyl, alkoxy, alkylcarbonyl,    alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy with 1 to 5 C    atoms,-   r is 0, 1, 2, 3 or 4,-   x and y are independently of each other 0 or identical or different    integers from 1 to 12,-   z is each and independently, 0 or 1, with z being 0 if the adjacent    x or y is 0.

Especially preferred are compounds of formula DRMa1, DRMa2 and DRMa3, inparticular those of formula DRMa1.

Preferably, one or more polymerizable liquid crystal molecules areselected from one monoreactive mesogenic compounds, more preferablyselected from compounds of formula MRM,P¹-Sp¹-MG-R  MRMwherein P¹, Sp¹ and MG have the meanings given in formula DRM,

-   R F, Cl, Br, I, —CN, —NO₂, —NCO, —NCS, —OCN, —SCN,    —C(═O)NR^(x)R^(y), —C(═O)X, —C(═O)OR^(x), —C(═O)R^(y), —NR^(x)R^(y),    —OH, —SF₅, optionally substituted silyl, straight chain or branched    alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or    alkoxycarbonyloxy with 1 to 12, preferably 1 to 6 C atoms, wherein    one or more H atoms are optionally replaced by F or Cl,-   X is halogen, preferably F or Cl, and-   R^(x) and R^(y) are independently of each other H or alkyl with 1 to    12 C-atoms.

Preferred compounds of formula MRM are selected from the followingformulae.

wherein P⁰, L, r, x, y and z are as defined in formula DRMa-1 to formulaDRMe,

-   R⁰ is alkyl, alkoxy, thioalkyl, alkylcarbonyl, alkoxycarbonyl,    alkylcarbonyloxy or alkoxycarbonyloxy with 1 or more, preferably 1    to 15 C atoms or denotes Y°,-   Y⁰ is F, Cl, CN, NO₂, OCH₃, OCN, SCN, SF₅, or mono- oligo- or    polyfluorinated alkyl or alkoxy with 1 to 4 C atoms,-   Z⁰ is —COO—, —OCO—, —CH₂CH₂—, —CF₂O—, —OCF₂—, —CH═CH—, —OCO—CH═CH—,    —CH═CH—COO—, or a single bond,-   A⁰ is, in case of multiple occurrence independently of one another,    1,4-phenylene that is unsubstituted or substituted with 1, 2, 3 or 4    groups L, or trans-1,4-cyclohexylene,-   u and v are independently of each other 0, 1 or 2,-   w is 0 or 1,    and wherein the benzene and naphthalene rings can additionally be    substituted with one or more identical or different groups L.

Further preferred are compounds of formula MRM1, MRM2, MRM3, MRM4, MRM5,MRM6, MRM7, MRM9 and MRM10, especially those of formula MRM1, MRM4,MRM6, and MRM7, and in particular those of formulae MRM1 and MRM7.

The compounds of the formulae P, DRM, MRM, and sub-formulae thereof canbe pre-pared analogously to processes known to the person skilled in theart and described in standard works of organic chemistry, such as, forexample, in Houben-Weyl, Methoden der organischen Chemie [Methods ofOrganic Chemistry], Thieme-Verlag, Stuttgart.

The proportion of said mono-, di- or multireactive liquid-crystallinecompounds in a polymerizable liquid crystal mixture as a whole, ispreferably in the range from 30 to 99.9% by weight, more preferably inthe range from 50 to 99.9% by weight and even more preferably in therange from 85 to 99.9% by weight.

In a preferred embodiment, the proportion of the di- or multireactivepolymerisable mesogenic compounds in a polymerizable liquid crystalmixture as a whole, is preferably in the range from 5 to 99% by weight,more preferably in the range from 10 to 97% by weight and even morepreferably in the range from 15 to 95% by weight.

In another preferred embodiment, the proportion of the monoreactivepolymerisable mesogenic compounds in a polymerizable liquid crystalmixture as a whole, is, if present, preferably in the range from 5 to80% by weight, more preferably in the range from 10 to 75% by weight andeven more preferably in the range from 15 to 70% by weight.

In another preferred embodiment, the proportion of the multireactivepolymerizable mesogenic compounds in a polymerizable liquid crystalmixture as a whole is, if present, preferably in the range from 1 to 30%by weight, more preferably in the range from 2 to 20% by weight and evenmore preferably in the range from 3 to 10% by weight.

In another preferred embodiment the polymerizable liquid crystal mixturedoes not contain polymerizable mesogenic compounds having more than twopolymerisable groups.

In another preferred embodiment the polymerizable liquid crystal mixturedoes not contain polymerizable mesogenic compounds having less than twopolymerisable groups.

In another preferred embodiment the polymerizable liquid crystal mixtureis an achiral material, i.e. it does not contain any chiralpolymerizable mesogenic compounds or other chiral compounds.

In a further preferred embodiment, the polymerizable liquid crystalmixture comprises at least one monoreactive mesogenic compound,preferably selected from formulae MRM-1, at least one direactivemesogenic compound, preferably selected from formula DRMa-1, and one ormore compounds of formula S.

In a further preferred embodiment, the polymerizable liquid crystalmixture comprises at least one monoreactive mesogenic compound,preferably selected from formula MRM-7, at least one direactivemesogenic compound, preferably selected from formula DRMa-1, and one ormore compounds of formula S.

In a further preferred embodiment, the polymerizable liquid crystalmixture comprises at least two monoreactive mesogenic compound,preferably selected from compounds of formulae MRM-1 and/or MRM-7, atleast one direactive mesogenic compound, preferably selected fromformula DRMa-1, and one or more compounds of formula S.

In a further preferred embodiment, the polymerizable liquid crystalmixture comprises at least two monoreactive mesogenic compounds,preferably selected from compounds of formulae MRM-1 and/or MRM-7, atleast two direactive mesogenic compounds, preferably selected fromcompounds of formula DRMa-1, and one or more compounds of formula S.

In a further preferred embodiment, the polymerizable liquid crystalmixture comprises at least two direactive mesogenic compounds,preferably selected from compounds of formula DRMa-1, and one or morecompounds of formula S.

In a further preferred embodiment, especially for negative opticaldispersion applications, the polymerizable liquid crystal mixture asdescribed above comprises additionally one or more compounds of formulaND,

wherein

-   U^(1,2) are independently of each other selected from

-   -   including their mirror images, wherein the rings U¹ and U² are        each bonded to the group —(B)_(q)— via the axial bond, and one        or two non-adjacent CH₂ groups in these rings are optionally        replaced by O and/or S, and the rings U¹ and U² are optionally        substituted by one or more groups L,

-   Q^(1,2) are independently of each other CH or SiH,

-   Q³ is C or Si,

-   B is in each occurrence independently of one another —C≡C—,    —CY¹═CY²— or an optionally substituted aromatic or heteroaromatic    group,

-   Y^(1,2) are independently of each other H, F, Cl, CN or R⁰,

-   q is an integer from 1 to 10, preferably 1, 2, 3, 4, 5, 6 or 7,

-   A¹⁻⁴ are independently of each other selected from non-aromatic,    aromatic or heteroaromatic carbocyclic or heterocyclic groups, which    are optionally substituted by one or more groups R⁵, and wherein    each of -(A¹-Z¹)_(m)-U¹-(Z²-A²)_(n)- and    -(A³-Z₃)_(o)-U²-(Z⁴-A⁴)_(p)- does not contain more aromatic groups    than non-aromatic groups and preferably does not contain more than    one aromatic group,

-   Z¹⁻⁴ are independently of each other —O—, —S—, —CO—, —COO—, —OCO—,    —O—COO—, —CO—NR⁰—, —NR⁰—CO—, —NR⁰—CO—NR⁰⁰—, —OCH₂—, —CH₂O—, —SCH₂—,    —CH₂S—, —CF₂O—, —OCF₂—, —CF₂S—, —SCF₂—, —CH₂CH₂—, —(CH₂)₃—,    —(CH₂)₄—, —CF₂CH₂—, —CH₂CF₂—, —CF₂CF₂—, —CH═CH—, —CY¹═CY²—, —CH═N—,    —N═CH—, —N═N—, —CH═CR⁰—, —C≡C—, —CH═CH—COO—, —OCO—CH═CH—, CR⁰R⁰⁰ or    a single bond,

-   R⁰ and R⁰⁰ are independently of each other H or alkyl with 1 to 12    C-atoms,

-   m and n are independently of each other 0, 1, 2, 3 or 4,

-   and p are independently of each other 0, 1, 2, 3 or 4,

-   R¹⁻⁵ are independently of each other identical or different groups    selected from H, halogen, —CN, —NC, —NCO, —NCS, —OCN, —SCN,    —C(═O)NR⁰R⁰⁰, —C(═O)X⁰, —C(═O)R⁰, —NH₂, —NR⁰R⁰⁰, —SH, —SR⁰, —SO₃H,    —SO₂R⁰, —OH, —NO₂, —CF₃, —SF₅, P-Sp-, optionally substituted silyl,    or carbyl or hydrocarbyl with 1 to 40 C atoms that is optionally    substituted and optionally comprises one or more hetero atoms, or    denote P or P-Sp-, or are substituted by P or P-Sp-, wherein the    compounds comprise at least one group R¹⁻⁵ denoting or being    substituted by P or P-Sp-,

-   P is a polymerisable group,

-   Sp is a spacer group or a single bond.

Preferably, the subgroups forming the bridging group B in formula ND arepreferably selected from groups having a bonding angle of 120° or more,preferably in the range of 180°. Very preferred are —C≡C— groups ordivalent aromatic groups connected to their adjacent groups inpara-position, like e.g. 1,4-phenylene, naphthalene-2,6-diyl,indane-2,6-diyl or thieno[3,2-b]thiophene-2,5-diyl.

Further possible subgroups include —CH═CH—, —CY¹═CY²—, —CH═N—, —N═CH—,—N═N— and —CH═CR⁰— wherein Y¹, Y², R⁰ have the meanings given above.

Preferably the bridging group, or —(B)_(q)— in formula ND, comprises oneor more groups selected from the group consisting of —C≡C—, optionallysubstituted 1,4-phenylene and optionally substituted9H-fluorene-2,7-diyl. The subgroups, or B in formula ND, are preferablyselected from the group consisting of —C≡C—, optionally substituted1,4-phenylene and optionally substituted 9H-fluorene-2,7-diyl, whereinin the fluorene group the H-atom in 9-position is optionally replaced bya carbyl or hydrocarbyl group.

Very preferably the bridging group, or —(B)_(q)— in formula ND, areselected from —C≡C—, —C≡C—C≡C—, —C≡C—C≡C—C≡C—, —C≡C—C≡C—C≡C—C≡C—,

wherein r is 0, 1, 2, 3 or 4 and L has the meaning as described below.

Preferably, the non-aromatic rings of the mesogenic groups where thebridging group is attached, like U¹ and U² in formula ND, are preferablyselected from

wherein R⁵ is as defined in formula ND.

Preferably, the aromatic groups A¹⁻⁴ in formula ND, may be mononuclear,i.e. having only one aromatic ring (like for example phenyl orphenylene), or polynuclear, i.e. having two or more fused rings (likefor example napthyl or naphthylene). Especially preferred are mono-, bi-or tricyclic aromatic or heteroaromatic groups with up to 25 C atomsthat may also comprise fused rings and that are optionally substituted.

Preferably, the non-aromatic carbocyclic and heterocyclic rings A¹⁻⁴ inthe compounds of formula ND, include those which are saturated (alsoreferred to as “fully saturated”), i.e. they do only contain C-atoms orhetero atoms connected by single bonds, and those which are unsaturated(also referred to as “partially saturated”), i.e. they also compriseC-atoms or hetero atoms connected by double bonds. The non-aromaticrings may also comprise one or more hetero atoms, preferably selectedfrom Si, O, N and S.

Preferably the non-aromatic and aromatic rings, or A¹⁻⁴ in formula ND,are selected from trans-1,4-cyclohexylene and 1,4-phenylene that isoptionally substituted with one or more groups L.

Very preferred are compounds of formula ND, wherein m and p are 1 and nand o are 1 or 2. Further preferred are compounds of formula ND, whereinm and p are 1 or 2 and n and o are 0. Further preferred are compoundswherein m, n, o and p are 2.

In the compounds of formula ND, the linkage groups connecting thearomatic and non-aromatic cyclic groups in the mesogenic groups, orZ¹⁻⁴, are preferably selected from —O—, —S—, —CO—, —COO—, —OCO—,—O—COO—, —CO—NR⁰—, —NR⁰—CO—, —NR⁰—CO—NR⁰—, —OCH₂—, —CH₂O—, —SCH₂—,—CH₂S—, —CF₂O—, —OCF₂—, —CF₂S—, —SCF₂—, —CH₂CH₂—, —(CH₂)₃—, —(CH₂)₄—,—CF₂CH₂—, —CH₂CF₂—, —CF₂CF₂—, —CH═CH—, —CY¹═CY²—, —CH═N—, —N═CH—, —N═N—,—CH═CR⁰—, —C≡C—, —CH═CH—COO—, —OCO—CH═CH—, CR⁰R⁰⁰ or a single bond, verypreferably from —COO—, —OCO— and a single bond.

Preferably, in the compounds of formula ND, the substituents on therings, such as L, are preferably selected from P-Sp-, F, Cl, Br, I, —CN,—NO₂, —NCO, —NCS, —OCN, —SCN, —O(′O)NR⁰R⁰⁰, —C(═O)X, —C(═O)OR⁰,—C(═O)R⁰, —NR⁰R⁰⁰, —OH, —SF₅, optionally substituted silyl, aryl orheteroaryl with 1 to 12, preferably 1 to 6 C atoms, and straight chainor branched alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl,alkylcarbonyloxy or alkoxycarbonyloxy with 1 to 12, preferably 1 to 6 Catoms, wherein one or more H atoms are optionally replaced by F or Cl,wherein R⁰ and R⁰⁰ are as defined in formula ND and X is halogen.

Preferably, the compounds of formula ND comprise one or more terminalgroups, like R¹⁻⁴, or substituents, like R⁵, that are substituted by twoor more polymerizable groups P or P-Sp- (multifunctional polymerizablegroups). Suitable multifunctional polymerizable groups of this type aredisclosed for example in U.S. Pat. No. 7,060,200 B1 or US 2006/0172090A1.

Very preferred compounds of formula ND are those of the following subformulae:

wherein R¹⁻⁵, A¹⁻⁴, Z¹⁻⁴, B, m, n, o, p and q have one the meaningsgiven above.

Especially preferred are compounds of the following sub formulae:

wherein Z has one of the meanings of Z¹ given above, R has one of themeanings of R¹ as given above that is different from P-Sp-, and P, Sp, Land r are as defined above, and the benzene rings in the mesogenicgroups are optionally substituted by one or more groups L as definedabove.

Preference is furthermore given to a polymerisable liquid crystallinemedium wherein the compounds of formula ND are selected from the groupof compounds of formula ND 25 or ND 26, in particular wherein Z denotes—COO—, r is in each occurrence 0, and P, Sp are as defined above.

P-Sp- in these preferred compounds is preferably P-Sp′—X′, with X′preferably being —O—, —COO— or —OCOO—.

The compounds of formula ND, its subformulae and suitable methods fortheir synthesis are disclosed in WO 2008/119427 A1.

The amount of compounds of formula ND in the polymerizable liquidcrystal mixture is preferably from 1 to 50%, very preferably from 1 to40%.

In a further preferred embodiment the polymerizable liquid crystalmixture optionally comprises one or more additives selected from thegroup consisting of further polymerisation initiators, antioxidants,surfactants, stabilisers, catalysts, sensitizers, inhibitors,chain-transfer agents, co-reacting monomers, reactive thinners,surface-active compounds, lubricating agents, wetting agents, dispersingagents, hydrophobing agents, adhesive agents, flow improvers, degassingor defoaming agents, deaerators, diluents, reactive diluents,auxiliaries, colourants, dyes, pigments and nanoparticles.

In another preferred embodiment, the polymerizable liquid crystalmixture optionally comprises one or more additives selected frompolymerisable non-mesogenic compounds (reactive thinners). The amount ofthese additives in the polymerizable liquid crystal mixture ispreferably from 0 to 30%, very preferably from 0 to 25%.

The reactive thinners used are not only substances which are referred toin the actual sense as reactive thinners, but also auxiliary compoundsalready mentioned above which contain one or more complementary reactiveunits or polymerizable groups P, for example hydroxyl, thiol-, or aminogroups, via which a reaction with the polymerisable units of theliquid-crystalline compounds can take place.

The substances, which are usually capable of photopolymerisation,include, for example, mono-, bi- and polyfunctional compounds containingat least one olefinic double bond. Examples thereof are vinyl esters ofcarboxylic acids, for example of lauric, myristic, palmitic and stearicacid, and of dicarboxylic acids, for example of succinic acid, adipicacid, allyl and vinyl ethers and methacrylic and acrylic esters ofmonofunctional alcohols, for example of lauryl, myristyl, palmityl andstearyl alcohol, and diallyl and divinyl ethers of bifunctionalalcohols, for example ethylene glycol and 1,4-butanediol.

Also suitable are, for example, methacrylic and acrylic esters ofpolyfunctional alcohols, in particular those which contain no furtherfunctional groups, or at most ether groups, besides the hydroxyl groups.Examples of such alcohols are bifunctional alcohols, such as ethyleneglycol, propylene glycol and their more highly condensedrepresentatives, for example diethylene glycol, triethylene glycol,dipropylene glycol, tripropylene glycol etc., butanediol, pentanediol,hexanediol, neopentyl glycol, alkoxylated phenolic compounds, such asethoxylated and propoxylated bisphenols, cyclohexanedimethanol,trifunctional and polyfunctional alcohols, such as glycerol,trimethylolpropane, butanetriol, trimethylolethane, pentaerythritol,ditrimethylolpropane, dipentaerythritol, sorbitol, mannitol, and thecorresponding alkoxylated, in particular ethoxylated and propoxylatedalcohols.

Other suitable reactive thinners are polyester (meth)acrylates, whichare the (meth)acrylic ester of polyesterols.

Examples of suitable polyesterols are those which can be prepared byesterification of polycarboxylic acids, preferably dicarboxylic acids,using polyols, preferably diols. The starting materials for suchhydroxyl-containing polyesters are known to the person skilled in theart. Dicarboxylic acids which can be employed are succinic, glutaricacid, adipic acid, sebacic acid, o-phthalic acid and isomers andhydrogenation products thereof, and esterifiable and transesterifiablederivatives of said acids, for example anhydrides and dialkyl esters.Suitable polyols are the abovementioned alcohols, preferablyethyleneglycol, 1,2- and 1,3-propylene glycol, 1,4-butanediol,1,6-hexanediol, neopentyl glycol, cyclohexanedimethanol and polyglycolsof the ethylene glycol and propylene glycol type.

Suitable reactive thinners are furthermore 1,4-divinylbenzene, triallylcyanurate, acrylic esters of tricyclodecenyl alcohol of the followingformula

also known under the name dihydrodicyclopentadienyl acrylate, and theallyl esters of acrylic acid, methacrylic acid and cyanoacrylic acid.

Of the reactive thinners, which are mentioned by way of example, thosecontaining photopolymerizable groups are used in particular and in viewof the abovementioned preferred compositions.

This group includes, for example, dihydric and polyhydric alcohols, forexample ethylene glycol, propylene glycol and more highly condensedrepresentatives thereof, for example diethylene glycol, triethyleneglycol, dipropylene glycol, tripropylene glycol etc., butanediol,pentanediol, hexanediol, neopentyl glycol, cyclohexanedimethanol,glycerol, trimethylolpropane, butanetriol, trimethylolethane,pentaerythritol, ditrimethylolpropane, dipentaerythritol, sorbitol,mannitol and the corresponding alkoxylated, in particular ethoxylatedand propoxylated alcohols.

The group furthermore also includes, for example, alkoxylated phenoliccompounds, for example ethoxylated and propoxylated bisphenols.

These reactive thinners may furthermore be, for example, epoxide orurethane (meth)acrylates.

Epoxide (meth)acrylates are, for example, those as obtainable by thereaction, known to the person skilled in the art, of epoxidized olefinsor poly- or diglycidyl ether, such as bisphenol A diglycidyl ether, with(meth)acrylic acid.

Urethane (meth)acrylates are, in particular, the products of a reaction,likewise known to the person skilled in the art, of hydroxylalkyl(meth)acrylates with poly- or diisocyanates.

Such epoxide and urethane (meth)acrylates are included amongst thecompounds listed above as “mixed forms”.

If reactive thinners are used, their amount and properties must bematched to the respective conditions in such a way that, on the onehand, a satisfactory desired effect, for example the desired colour ofthe composition according to the invention, is achieved, but, on theother hand, the phase behaviour of the liquid-crystalline composition isnot excessively impaired. The low-crosslinking (high-crosslinking)liquid-crystalline compositions can be prepared, for example, usingcorresponding reactive thinners, which have a relatively low (high)number of reactive units per molecule.

The group of diluents include, for example:

C1-C4-alcohols, for example methanol, ethanol, n-propanol, isopropanol,butanol, isobutanol, sec-butanol and, in particular, the C5-C12-alcoholsn-pentanol, n-hexanol, n-heptanol, n-octanol, n-nonanol, n-decanol,n-undecanol and n-dodecanol, and isomers thereof, glycols, for example1,2-ethylene glycol, 1,2- and 1,3-propylene glycol, 1,2-, 2,3- and1,4-butylene glycol, di- and triethylene glycol and di- and tripropyleneglycol, ethers, for example methyl tert-butyl ether, 1,2-ethylene glycolmono- and dimethyl ether, 1,2-ethylene glycol mono- and -diethylether,3-methoxypropanol, 3-isopropoxypropanol, tetrahydrofuran and dioxane,ketones, for example acetone, methyl ethyl ketone, methyl isobutylketone and diacetone alcohol (4-hydroxy-4-methyl-2-pentanone),C1-C5-alkyl esters, for example methyl acetate, ethyl acetate, propylacetate, butyl acetate and amyl acetate, aliphatic and aromatichydrocarbons, for example pentane, hexane, heptane, octane, isooctane,petroleum ether, toluene, xylene, ethylbenzene, tetralin, decalin,dimethylnaphthalene, white spirit, Shellsol® and Solvesso® mineral oils,for example gasoline, kerosine, diesel oil and heating oil, but alsonatural oils, for example olive oil, soya oil, rapeseed oil, linseed oiland sunflower oil.

It is of course also possible to use mixtures of these diluents in thecompositions according to the invention.

So long as there is at least partial miscibility, these diluents canalso be mixed with water. Examples of suitable diluents here areC1-C4-alcohols, for example methanol, ethanol, n-propanol, isopropanol,butanol, isobutanol and sec-butanol, glycols, for example 1,2-ethyleneglycol, 1,2- and 1,3-propylene glycol, 1,2-, 2,3- and 1,4-butyleneglycol, di- and triethylene glycol, and di- and tripropylene glycol,ethers, for example tetrahydrofuran and dioxane, ketones, for exampleacetone, methyl ethyl ketone and diacetone alcohol(4-hydroxy-4-methyl-2-pentanone), and C1-C4-alkyl esters, for examplemethyl, ethyl, propyl and butyl acetate.

The diluents are optionally employed in a proportion of from about 0 to10.0% by weight, preferably from about 0 to 5.0% by weight, based on thetotal weight of the polymerisable LC material.

The antifoams and deaerators (c1)), lubricants and flow auxiliaries(c2)), thermally curing or radiation-curing auxiliaries (c3)), substratewetting auxiliaries (c4)), wetting and dispersion auxiliaries (c5)),hydrophobicizing agents (c6)), adhesion promoters (c7)) and auxiliariesfor promoting scratch resistance (c8)) cannot strictly be delimited fromone another in their action.

For example, lubricants and flow auxiliaries often also act as antifoamsand/or deaerators and/or as auxiliaries for improving scratchresistance. Radiation-curing auxiliaries can also act as lubricants andflow auxiliaries and/or deaerators and/or as substrate wettingauxiliaries. In individual cases, some of these auxiliaries can alsofulfil the function of an adhesion promoter (c8)).

Corresponding to the above-said, a certain additive can therefore beclassified in a number of the groups c1) to c8) described below.

The antifoams in group c1) include silicon-free and silicon-containingpolymers. The silicon-containing polymers are, for example, unmodifiedor modified polydialkylsiloxanes or branched copolymers, comb or blockcopolymers comprising polydialkylsiloxane and polyether units, thelatter being obtainable from ethylene oxide or propylene oxide.

The deaerators in group c1) include, for example, organic polymers, forexample polyethers and polyacrylates, dialkylpolysiloxanes, inparticular dimethylpolysiloxanes, organically modified polysiloxanes,for example arylalkyl-modified polysiloxanes, and fluorosilicones.

The action of the antifoams is essentially based on preventing foamformation or destroying foam that has already formed. Antifoamsessentially work by promoting coalescence of finely divided gas or airbubbles to give larger bubbles in the medium to be deaerated, forexample the compositions according to the invention, and thus accelerateescape of the gas (of the air). Since antifoams can frequently also beemployed as deaerators and vice versa, these additives have beenincluded together under group c1).

Such auxiliaries are, for example, commercially available from Tego asTEGO® Foamex 800, TEGO® Foamex 805, TEGO® Foamex 810, TEGO® Foamex 815,TEGO® Foamex 825, TEGO® Foamex 835, TEGO® Foamex 840, TEGO® Foamex 842,TEGO® Foamex 1435, TEGO® Foamex 1488, TEGO® Foamex 1495, TEGO® Foamex3062, TEGO® Foamex 7447, TEGO® Foamex 8020, Tego® Foamex N, TEGO® FoamexK 3, TEGO® Antifoam 2-18, TEGO® Antifoam 2-18, TEGO® Antifoam 2-57,TEGO® Antifoam 2-80, TEGO® Antifoam 2-82, TEGO® Antifoam 2-89, TEGO®Antifoam 2-92, TEGO® Antifoam 14, TEGO® Antifoam 28, TEGO® Antifoam 81,TEGO® Antifoam D 90, TEGO® Antifoam 93, TEGO® Antifoam 200, TEGO®Antifoam 201, TEGO® Antifoam 202, TEGO® Antifoam 793, TEGO® Antifoam1488, TEGO® Antifoam 3062, TEGOPREN® 5803, TEGOPREN® 5852, TEGOPREN®5863, TEGOPREN® 7008, TEGO® Antifoam 1-60, TEGO® Antifoam 1-62, TEGO®Antifoam 1-85, TEGO® Antifoam 2-67, TEGO® Antifoam WM 20, TEGO® Antifoam50, TEGO® Antifoam 105, TEGO® Antifoam 730, TEGO® Antifoam MR 1015,TEGO® Antifoam MR 1016, TEGO® Antifoam 1435, TEGO® Antifoam N, TEGO®Antifoam KS 6, TEGO® Antifoam KS 10, TEGO® Antifoam KS 53, TEGO®Antifoam KS 95, TEGO® Antifoam KS 100, TEGO® Antifoam KE 600, TEGO®Antifoam KS 911, TEGO® Antifoam MR 1000, TEGO® Antifoam KS 1100, Tego®Airex 900, Tego® Airex 910, Tego® Airex 931, Tego® Airex 935, Tego®Airex 936, Tego® Airex 960, Tego® Airex 970, Tego® Airex 980 and Tego®Airex 985 and from BYK as BYK®-011, BYK®-019, BYK®-020, BYK®-021,BYK®-022, BYK®-023, BYK®-024, BYK®-025, BYK®-027, BYK®-031, BYK®-032,BYK®-033, BYK®-034, BYK®-035, BYK®-036, BYK®-037, BYK®-045, BYK®-051,BYK®-052, BYK®-053, BYK®-055, BYK®-057, BYK®-065, BYK®-066, BYK®-070,BYK®-080, BYK®-088, BYK®-141 and BYK®-A 530.

The auxiliaries in group c1) are optionally employed in a proportion offrom about 0 to 3.0% by weight, preferably from about 0 to 2.0% byweight, based on the total weight of the polymerisable LC material.

In group c2), the lubricants and flow auxiliaries typically includesilicon-free, but also silicon-containing polymers, for examplepolyacrylates or modifiers, low-molecular-weight polydialkylsiloxanes.The modification consists in some of the alkyl groups having beenreplaced by a wide variety of organic radicals. These organic radicalsare, for example, polyethers, polyesters or even long-chain(fluorinated)alkyl radicals, the former being used the most frequently.

The polyether radicals in the correspondingly modified polysiloxanes areusually built up from ethylene oxide and/or propylene oxide units.Generally, the higher the proportion of these alkylene oxide units inthe modified polysiloxane, the more hydrophilic is the resultantproduct.

Such auxiliaries are, for example, commercially available from Tego asTEGO® Glide 100, TEGO® Glide ZG 400, TEGO® Glide 406, TEGO® Glide 410,TEGO® Glide 411, TEGO® Glide 415, TEGO® Glide 420, TEGO® Glide 435,TEGO® Glide 440, TEGO® Glide 450, TEGO® Glide A 115, TEGO® Glide B 1484(can also be used as antifoam and deaerator), TEGO® Flow ATF, TEGO® Flow300, TEGO® Flow 460, TEGO® Flow 425 and TEGO® Flow ZFS 460. Suitableradiation-curable lubricants and flow auxiliaries, which can also beused to improve the scratch resistance, are the products TEGO® Rad 2100,TEGO® Rad 2200, TEGO® Rad 2500, TEGO® Rad 2600 and TEGO® Rad 2700, whichare likewise obtainable from TEGO.

Such-auxiliaries are also available, for example, from BYK as BYK®-300BYK®-306, BYK®-307, BYK®-310, BYK®-320, BYK®-333, BYK®-341, Byk® 354,Byk®361, Byk®361N, BYK®388.

Such-auxiliaries are also available, for example, from 3M as FC4430®.

Such-auxiliaries are also available, for example, from Cytonix asFluorN®561 or FluorN®562.

Such-auxiliaries are also available, for example, from Merck KGaA asTivida® FL 2300 and Tivida® FL 2500

The auxiliaries in group c2) are optionally employed in a proportion offrom about 0 to 3.0% by weight, preferably from about 0 to 2.0% byweight, based on the total weight of the polymerisable LC material.

In group c3), the radiation-curing auxiliaries include, in particular,polysiloxanes having terminal double bonds which are, for example, aconstituent of an acrylate group. Such auxiliaries can be crosslinked byactinic or, for example, electron radiation. These auxiliaries generallycombine a number of properties together. In the uncrosslinked state,they can act as antifoams, deaerators, lubricants and flow auxiliariesand/or substrate wetting auxiliaries, while, in the crosslinked state,they increase, in particular, the scratch resistance, for example ofcoatings or films which can be produced using the compositions accordingto the invention. The improvement in the gloss properties, for exampleof precisely those coatings or films, is regarded essentially as aconsequence of the action of these auxiliaries as antifoams, deaeratorsand/or lubricants and flow auxiliaries (in the uncrosslinked state).

Examples of suitable radiation-curing auxiliaries are the products TEGO®Rad 2100, TEGO® Rad 2200, TEGO® Rad 2500, TEGO® Rad 2600 and TEGO® Rad2700 available from TEGO and the product BYK®-371 available from BYK.

Thermally curing auxiliaries in group c3) contain, for example, primaryOH groups, which are able to react with isocyanate groups, for exampleof the binder.

Examples of thermally curing auxiliaries, which can be used, are theproducts BYK®-370, BYK®-373 and BYK®-375 available from BYK.

The auxiliaries in group c3) are optionally employed in a proportion offrom about 0 to 5.0% by weight, preferably from about 0 to 3.0% byweight, based on the total weight of the polymerisable LC material.

The substrate wetting auxiliaries in group c4) serve, in particular, toincrease the wettability of the substrate to be printed or coated, forexample, by printing inks or coating compositions, for examplecompositions according to the invention. The generally attendantimprovement in the lubricant and flow behaviour of such printing inks orcoating compositions has an effect on the appearance of the finished(for example crosslinked) print or coating.

A wide variety of such auxiliaries are commercially available, forexample from Tego as TEGO® Wet KL 245, TEGO® Wet 250, TEGO® Wet 260 andTEGO® Wet ZFS 453 and from BYK as BYK®-306, BYK®-307, BYK®-310,BYK®-333, BYK®-344, BYK®-345, BYK®-346 and Byk®-348.

The auxiliaries in group c4) are optionally employed in a proportion offrom about 0 to 3.0% by weight, preferably from about 0 to 1.5% byweight, based on the total weight of the liquid-crystalline composition.

The wetting and dispersion auxiliaries in group c5) serve, inparticular, to prevent the flooding and floating and the sedimentationof pigments and are therefore, if necessary, suitable in particular inpigmented compositions.

These auxiliaries stabilize pigment dispersions essentially throughelectrostatic repulsion and/or steric hindrance of the pigment particlescontaining these additives, where, in the latter case, the interactionof the auxiliary with the ambient medium (for example binder) plays amajor role.

Since the use of such wetting and dispersion auxiliaries is commonpractice, for example in the technical area of printing inks and paints,the selection of a suitable auxiliary of this type generally does notpresent the person skilled in the art with any difficulties, if they areused.

Such wetting and dispersion auxiliaries are commercially available, forexample from Tego, as TEGO® Dispers 610, TEGO® Dispers 610 S, TEGO®Dispers 630, TEGO® Dispers 700, TEGO® Dispers 705, TEGO® Dispers 710,TEGO® Dispers 720 W, TEGO® Dispers 725 W, TEGO® Dispers 730 W, TEGO®Dispers 735 W and TEGO® Dispers 740 W and from BYK as Disperbyk®,Disperbyk®-107, Disperbyk®-108, Disperbyk®-110, Disperbyk®-111,Disperbyk®-115, Disperbyk®-130, Disperbyk®-160, Disperbyk®-161,Disperbyk®-162, Disperbyk®-163, Disperbyk®-164, Disperbyk®-165,Disperbyk®-166, Disperbyk®-167, Disperbyk®-170, Disperbyk®-174,Disperbyk®-180, Disperbyk®-181, Disperbyk®-182, Disperbyk®-183,Disperbyk®-184, Disperbyk®-185, Disperbyk®-190, Anti-Terra®-U,Anti-Terra®-U 80, Anti-Terra®-P, Anti-Terra®-203, Anti-Terra®-204,Anti-Terra®-206, BYK®-151, BYK®-154, BYK®-155, BYK®-P 104 S, BYK®-P 105,Lactimon®, Lactimon®-WS and Bykumen®.

The amount of the auxiliaries in group c5) used on the mean molecularweight of the auxiliary. In any case, a preliminary experiment istherefore advisable, but this can be accomplished simply by the personskilled in the art.

The hydrophobicizing agents in group c6) can be used to givewater-repellent properties to prints or coatings produced, for example,using compositions according to the invention. This prevents or at leastgreatly suppresses swelling due to water absorption and thus a changein, for example, the optical properties of such prints or coatings. Inaddition, when the composition is used, for example, as a printing inkin offset printing, water absorption can thereby be prevented or atleast greatly reduced.

Such hydrophobicizing agents are commercially available, for example,from Tego as Tego® Phobe WF, Tego® Phobe 1000, Tego® Phobe 1000 S, Tego®Phobe 1010, Tego® Phobe 1030, Tego® Phobe 1010, Tego® Phobe 1010, Tego®Phobe 1030, Tego® Phobe 1040, Tego® Phobe 1050, Tego® Phobe 1200, Tego®Phobe 1300, Tego® Phobe 1310 and Tego® Phobe 1400.

The auxiliaries in group c6) are optionally employed in a proportion offrom about 0 to 5.0% by weight, preferably from about 0 to 3.0% byweight, based on the total weight of the polymerisable LC material.

Further adhesion promoters from group c7) serve to improve the adhesionof two interfaces in contact. It is directly evident from this thatessentially the only fraction of the adhesion promoter that is effectiveis that located at one or the other or at both interfaces. If, forexample, it is desired to apply liquid or pasty printing inks, coatingcompositions or paints to a solid substrate, this generally means thatthe adhesion promoter must be added directly to the latter or thesubstrate must be pre-treated with the adhesion promoters (also known aspriming), i.e. this substrate is given modified chemical and/or physicalsurface properties.

If the substrate has previously been primed with a primer, this meansthat the interfaces in contact are that of the primer on the one handand of the printing ink or coating composition or paint on the otherhand. In this case, not only the adhesion properties between thesubstrate and the primer, but also between the substrate and theprinting ink or coating composition or paint play a part in adhesion ofthe overall multilayer structure on the substrate.

Adhesion promoters in the broader sense which may be mentioned are alsothe substrate wetting auxiliaries already listed under group c4), butthese generally do not have the same adhesion promotion capacity.

In view of the widely varying physical and chemical natures ofsubstrates and of printing inks, coating compositions and paintsintended, for example, for their printing or coating, the multiplicityof adhesion promoter systems is not surprising.

Adhesion promoters based on silanes are, for example,3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane,3-aminopropylmethyldiethoxysilane,N-aminoethyl-3-aminopropyltrimethoxysilane,N-aminoethyl-3-aminopropylmethyldimethoxysilane,N-methyl-3-aminopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane,3-methacryloyloxypropyltrimethoxysilane,3-glycidyloxypropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane,3-chloropropyltrimethoxysilane and vinyltrimethoxysilane. These andother silanes are commercially available from Hüls, for example underthe tradename DYNASILAN®.

Corresponding technical information from the manufacturers of suchadditives should generally be used or the person skilled in the art canobtain this information in a simple manner through correspondingpreliminary experiments.

However, if these additives are to be added as auxiliaries from groupc7) to the polymerisable LC materials according to the invention, theirproportion optionally corresponds to from about 0 to 5.0% by weight,based on the total weight of the polymerisable LC material. Theseconcentration data serve merely as guidance, since the amount andidentity of the additive are determined in each individual case by thenature of the substrate and of the printing/coating composition.Corresponding technical information is usually available from themanufacturers of such additives for this case or can be determined in asimple manner by the person skilled in the art through correspondingpreliminary experiments.

The auxiliaries for improving the scratch resistance in group c8)include, for example, the abovementioned products TEGO® Rad 2100, TEGO®Rad 2200, TEGO® Rad 2500, TEGO® Rad 2600 and TEGO® Rad 2700, which areavailable from Tego.

For these auxiliaries, the amount data given for group c3) are likewisesuitable, i.e. these additives are optionally employed in a proportionof from about 0 to 5.0% by weight, preferably from about 0 to 3.0% byweight, based on the total weight of the liquid-crystalline composition.

Examples that may be mentioned of further light, heat and/or oxidationstabilizers are the following:

alkylated monophenols, such as 2,6-di-tert-butyl-4-methylphenol,2-tert-butyl-4,6-dimethylphenol, 2,6-di-tert-butyl-4-ethylphenol,2,6-di-tert-butyl-4-n-butylphenol, 2,6-di-tert-butyl-4-isobutylphenol,2,6-dicyclopentyl-4-methylphenol,2-(α-methylcyclohexyl)-4,6-dimethylphenol,2,6-dioctadecyl-4-methylphenol, 2,4,6-tricyclohexylphenol,2,6-di-tert-butyl-4-methoxymethylphenol, nonylphenols which have alinear or branched side chain, for example 2,6-dinonyl-4-methylphenol,2,4-dimethyl-6-(1′-methylundec-1′-yl)phenol,2,4-dimethyl-6-(1′-methylheptadec-1′-yl)phenol,2,4-dimethyl-6-(1′-methyltridec-1′-yl)phenol and mixtures of thesecompounds, alkylthiomethylphenols, such as2,4-dioctylthiomethyl-6-tert-butylphenol,2,4-dioctylthiomethyl-6-methylphenol,2,4-dioctylthiomethyl-6-ethylphenol and2,6-didodecylthiomethyl-4-nonylphenol,Hydroquinones and alkylated hydroquinones, such as2,6-di-tert-butyl-4-methoxyphenol, 2,5-di-tert-butylhydroquinone,2,5-di-tert-amylhydrocrainone, 2,6-diphenyl-4-octadecyloxyphenol,2,6-di-tert-butylhydroquinone, 2,5-di-tert-butyl-4-hydroxyanisole,3,5-di-tert-butyl-4-hydroxyanisole, 3,5-di-tert-butyl-4-hydroxyphenylstearate and bis(3,5-di-tert-butyl-4-hydroxyphenyl)adipate,Tocopherols, such as α-tocopherol, β-tocopherol, γ-tocopherol,δ-tocopherol and mixtures of these compounds, and tocopherolderivatives, such as tocopheryl acetate, succinate, nicotinate andpolyoxyethylenesuccinate (“tocofersolate”),hydroxylated diphenyl thioethers, such as2,2′-thiobis(6-tert-butyl-4-methylphenol), 2,2′-thiobis(4-octylphenol),4,4′-thiobis(6-tert-butyl-3-methylphenol),4,4′-thiobis(6-tert-butyl-2-methylphenol),4,4′-thiobis(3,6-di-sec-amylphenol) and4,4′-bis(2,6-dimethyl-4-hydroxyphenyl)disulfide,Alkylidenebisphenols, such as2,2′-methylenebis(6-tert-butyl-4-methylphenol),2,2′-methylenebis(6-tert-butyl-4-ethylphenol),2,2′-methylenebis[4-methyl-6-(α-methylcyclohexyl)phenol],2,2′-methylenebis(4-methyl-6-cyclohexylphenol),2,2′-methylenebis(6-nonyl-4-methylphenol),2,2′-methylenebis(4,6-di-tert-butylphenol),2,2-ethylidenebis(4,6-di-tert-butylphenol),2,2′-ethylidenebis(6-tert-butyl-4-isobutylphenol),2,2′-methylenebis[6-(α-methylbenzyl)-4-nonylphenol],2,2′-methylenebis[6-(α,α-dimethylbenzyl)-4-nonylphenol],4,4′-methylenebis(2,6-di-tert-butylphenol),4,4′-methylenebis(6-tert-butyl-2-methylphenol),1,1-bis(5-tert-butyl-4-hydroxy-2-methylphenyl)butane,2,6-bis(3-tert-butyl-5-methyl-2-hydroxybenzyl)-4-methylphenol,1,1,3-tris(5-tert-butyl-4-hydroxy-2-methylphenyl)butane,1,1-bis(5-tert-butyl-4-hydroxy-2-methylphenyl)-3-n-dodecyl-mercaptobutane,ethylene glycol bis[3,3-bis(3′-tert-butyl-4′-hydroxyphenyl)butyrate],bis(3-tert-butyl-4-hydroxy-5-methylphenyl)dicyclopentadiene,bis[2-(3′-tert-butyl-2′-hydroxy-5′-methylbenzyl)-6-tert-butyl-4-methylphenyl]terephthalate,1,1-bis(3,5-dimethyl-2-hydroxyphenyl)butane,2,2-bis(3,5-di-tert-butyl-4-hydroxyphenyl)propane,2,2-bis(5-tert-butyl-4-hydroxy-2-methylphenyl)-4-n-dodecyl-mercaptobutaneand 1,1,5,5-tetrakis(5-tert-butyl-4-hydroxy-2-methylphenyl)pentane,O-, N- and S-benzyl compounds, such as3,5,3′,5′-tetra-tert-butyl-4,4′-dihydroxydibenzyl ether, octadecyl4-hydroxy-3,5-dimethylbenzylmercaptoacetate, tridecyl4-hydroxy-3,5-di-tert-butylbenzylmercaptoacetate,tris(3,5-di-tert-butyl-4-hydroxybenzyl)amine,bis(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)dithioterephthalate,bis(3,5-di-tert-butyl-4-hydroxybenzyl)sulfide andisooctyl-3,5-di-tert-butyl-4-hydroxybenzylmercaptoacetate,aromatic hydroxybenzyl compounds, such as1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)-2,4,6-trimethyl-benzene,1,4-bis(3,5-di-tert-butyl-4-hydroxybenzyl)-2,3,5,6-tetramethyl-benzeneand 2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)phenol,Triazine compounds, such as2,4-bis(octylmercapto)-6-(3,5-di-tert-butyl-4-hydroxyanilino)-1,3,5-triazine,2-octylmercapto-4,6-bis(3,5-di-tert-butyl-4-hydroxyanilino)-1,3,5-triazine,2-octylmercapto-4,6-bis(3,5-di-tert-butyl-4-hydroxyphenoxy)-1,3,5-triazine,2,4,6-tris(3,5-di-tert-butyl-4-hydroxyphenoxy)-1,2,3-triazine,1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)isocyanurate,1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)isocyanurate,2,4,6-tris(3,5-di-tert-butyl-4-hydroxyphenylethyl)-1,3,5-triazine,1,3,5-tris-(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)hexahydro-1,3,5-triazine,1,3,5-tris(3,5-dicyclohexyl-4-hydroxybenzyl)isocyanurate and1,3,5-tris(2-hydroxyethyl)isocyanurate,Benzylphosphonates, such as dimethyl2,5-di-tert-butyl-4-hydroxybenzylphosphonate, diethyl3,5-di-tert-butyl-4-hydroxybenzylphosphonate, dioctadecyl3,5-di-tert-butyl-4-hydroxybenzylphosphonate and dioctadecyl5-tert-butyl-4-hydroxy-3-methylbenzylphosphonate,Acylaminophenols, such as 4-hydroxylauroylanilide,4-hydroxystearoylanilide and octylN-(3,5-di-tert-butyl-4-hydroxyphenyl)carbamate,Propionic and acetic esters, for example of monohydric or polyhydricalcohols, such as methanol, ethanol, n-octanol, i-octanol, octadecanol,1,6-hexanediol, 1,9-nonanediol, ethylene glycol, 1,2-propanediol,neopentyl glycol, thiodiethylene glycol, diethylene glycol, triethyleneglycol, pentaerythritol, tris(hydroxyethyl)isocyanurate,N,N′-bis(hydroxyethyl)oxalamide, 3-thiaundecanol, 3-thiapentadecanol,trimethylhexanediol, trimethylolpropane and4-hydroxymethyl-1-phospha-2,6,7-trioxabicyclo[2.2.2]-octane,Propionamides based on amine derivatives, such asN,N′-bis(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)hexamethylenediamine,N,N′-bis(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)trimethylenediamineand N,N′-bis(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)hydrazine,Ascorbic acid (Vitamin C) and ascorbic acid derivatives, such asascorbyl palmitate, laurate and stearate, and ascorbyl sulfate andphosphate,Antioxidants based on amine compounds, such asN,N′-diisopropyl-p-phenylenediamine,N,N′-di-sec-butyl-p-phenylenediamine,N,N′-bis(1,4-dimethylpentyl)-p-phenylenediamine,N,N′-bis(1-ethyl-3-methylpentyl)-p-phenylenediamine,N,N′-bis(1-methylheptyl)-p-phenylenediamine,N,N′-dicyclohexyl-p-phenylenediamine, N,N′-diphenyl-p-phenylenediamine,N,N′-bis(2-naphthyl)-p-phenylenediamine,N-isopropyl-N′-phenyl-p-phenylenediamine,N-(1,3-dimethylbutyl)-N′-phenyl-p-phenylenediamine,N-(1-methylheptyl)-N′-phenyl-p-phenylenediamine,N-cyclohexyl-N′-phenyl-p-phenylenediamine,4-(p-toluenesulfamoyl)diphenylamine,N,N′-dimethyl-N,N′-di-sec-butyl-p-phenylenediamine, diphenylamine,N-allyldiphenylamine, 4-isopropoxydiphenylamine,N-phenyl-1-naphthylamine, N-(4-tert-octylphenyl)-1-naphthylamine,N-phenyl-2-naphthylamine, octyl-substituted diphenylamine, such asp,p′-di-tert-octyldiphenylamine, 4-n-butylaminophenol,4-butyrylaminophenol, 4-nonanoylaminophenol, 4-dodecanoylaminophenol,4-octadecanoylaminophenol, bis[4-methoxyphenyl)amine,2,6-di-tert-butyl-4-dimethylaminomethylphenol,2,4-diaminodiphenylmethane, 4,4′-diaminodiphenylmethane,N,N,N′,N′-tetramethyl-4,4′-diaminodiphenylmethane,1,2-bis[(2-methylphenyl)amino]ethane, 1,2-bis(phenylamino)propane,(o-tolyl)biguanide, bis[4-(1′,3′-dimethylbutyl)phenyl]amine,tert-octyl-substituted N-phenyl-1-naphthylamine, a mixture of mono- anddialkylated tert-butyl/tert-octyldiphenylamine, a mixture of mono- anddialkylated nonyldiphenylamine, a mixture of mono- and dialkylateddodecyldiphenylamine, a mixture of mono- and dialkylatedisopropyl/isohexyldiphenylamine, a mixture of mono- and dialkylatedtert-butyldiphenylamine, 2,3-dihydro-3,3-dimethyl-4H-1,4-benzothiazine,phenothiazine, a mixture of mono- and dialkylatedtert-butyl/tert-octylphenothiazine, a mixture of mono- and dialkylatedtert-octylphenothiazine, N-allylphenothiazine,N,N,N′,N′-tetraphenyl-1,4-diaminobut-2-ene,N,N-bis(2,2,6,6-tetramethylpiperidin-4-yl)hexamethylenediamine,bis(2,2,6,6-tetramethylpiperidin-4-yl)sebacate,2,2,6,6-tetramethylpiperidin-4-one and2,2,6,6-tetramethylpiperidin-4-ol,Phosphines, Phosphites and phosphonites, such as triphenylphosninetriphenylphosphite, diphenyl alkyl phosphite, phenyl dialkyl phosphite,tris(nonylphenyl)phosphite, trilauryl phosphite, trioctadecyl phosphite,distearyl pentaerythritol diphosphite,tris(2,4-di-tert-butylphenyl)phosphite, diisodecyl pentaerythritoldiphosphite, bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite,bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite,diisodecyloxy pentaerythritol diphosphite,bis(2,4-di-tert-butyl-6-methylphenyl)pentaerythritol diphosphite,bis(2,4,6-tris(tert-butylphenyl))pentaerythritol diphosphite, tristearylsorbitol triphosphite,tetrakis(2,4-di-tert-butylphenyl)4,4′-biphenylenediphosphonite,6-isooctyloxy-2,4,8,10-tetra-tert-butyl-12H-dibenz[d,g]-1,3,2-dioxaphosphocine,6-fluoro-2,4,8,10-tetra-tert-butyl-12-methyl-dibenz[d,g]-1,3,2-dioxaphosphocine,bis(2,4-di-tert-butyl-6-methylphenyl)methyl phosphite andbis(2,4-di-tert-butyl-6-methylphenyl)ethyl phosphite,2-(2′-Hydroxyphenyl)benzotriazoles, such as2-(2′-hydroxy-5′-methylphenyl)benzotriazole,2-(3′,5′-di-tert-butyl-2′-hydroxyphenyl)benzotriazole,2-(5′-tert-butyl-2′-hydroxyphenyl)benzotriazole,2-(2′-hydroxy-5′-(1,1,3,3-tetramethylbutyl)phenyl)benzotriazole,2-(3′,5′-di-tert-butyl-2′-hydroxyphenyl)-5-chlorobenzotriazole,2-(3′-tert-butyl-2′-hydroxy-5′-methylphenyl)-5-chlorobenzotriazole,2-(3′-sec-butyl-5′-tert-butyl-2′-hydroxyphenyl)benzotriazole,2-(2′-hydroxy-4′-octyloxyphenyl)benzotriazole,2-(3′,5′-di-tert-amyl-2′-hydroxyphenyl)benzotriazole,2-(3,5′-bis-(α,α-dimethylbenzyl)-2′-hydroxyphenyl)benzotriazole, amixture of2-(3′-tert-butyl-2′-hydroxy-5′-(2-octyloxycarbonylethyl)phenyl)-5-chlorobenzotriazole,2-(3′-tert-butyl-5′-[2-(2-ethyl hexyloxy)carbonylethyl]-2′-hydroxyphenyl)-5-chlorobenzotriazole,2-(3′-tert-butyl-2′-hydroxy-5′-(2-methoxycarbonylethyl)phenyl)-5-chlorobenzotriazole,2-(3′-tert-butyl-2′-hydroxy-5′-(2-methoxycarbonylethyl)phenyl)benzotriazole,2-(3′-tert-butyl-2′-hydroxy-5′-(2-octyloxycarbonylethyl)phenyl)benzotriazole,2-(3′-tert-butyl-5′-[2-(2-ethylhexyloxy)carbonylethyl]-2′-hydroxyphenyl)benzotriazole, 2-(3′-dodecyl-2′-hydroxy-5′-methylphenyl)benzotriazole and2-(3′-tert-butyl-2′-hydroxy-5′-(2-isooctyloxycarbonylethyl)phenylbenzotriazole,2,2′-methylenebis[4-(1,1,3,3-tetramethylbutyl)-6-benzotriazol-2-ylphenol];the product of complete esterification of2-[3′-tert-butyl-5′-(2-methoxycarbonylethyl)-2′-hydroxyphenyl]-2H-benzotriazolewith polyethylene glycol 300;sulfur-containing peroxide scavengers and sulfur-containingantioxidants, such as esters of 3,3′-thiodipropionic acid, for examplethe lauryl, stearyl, myristyl and tridecyl esters, mercaptobenzimidazoleand the zinc salt of 2-mercaptobenzimidazole, dibutylzincdithiocarbamates, dioctadecyl disulfide and pentaerythritoltetrakis(β-dodecylmercapto)propionate,Esters of unsubstituted and substituted benzoic acids, such as4-tert-butylphenyl salicylate, phenyl salicylate, octylphenylsalicylate, dibenzoylresorcinol, bis(4-tert-butylbenzoyl)resorcinol,benzoylresorcinol, 2,4-di-tert-butylphenyl3,5-di-tert-butyl-4-hydroxybenzoate,hexadecyl-3,5-di-tert-butyl-4-hydroxybenzoate,octadecyl-3,5-di-tert-butyl-4-hydroxybenzoate and2-methyl-4,6-di-tert-butylphenyl-3,5-di-tert-butyl-4-hydroxybenzoate,Acrylates, such as ethyl α-cyano-β,β-diphenylacrylate, isooctylα-cyano-β,β-diphenylacrylate, methyl α-methoxycarbonylcinnamate, methylα-cyano-β-methyl-p-methoxycinnamate,butyl-α-cyano-β-methyl-p-methoxycinnamate andmethyl-α-methoxycarbonyl-p-methoxycinnamate, sterically hindered amines,such as bis(2,2,6,6-tetramethylpiperidin-4-yl)sebacate,bis(2,2,6,6-tetramethylpiperidin-4-yl)succinate,bis(1,2,2,6,6-pentamethylpiperidin-4-yl)sebacate,bis(1-octyloxy-2,2,6,6-tetramethylpiperidin-4-yl)sebacate,bis(1,2,2,6,6-pentamethylpiperidin-4-yl)-n-butyl-3,5-di-tert-butyl-4-hydroxybenzylmalonate,the condensation product of1-(2-hydroxyethyl)-2,2,6,6-tetramethyl-4-hydroxypiperidine and succinicacid, the condensation product ofN,N′-bis(2,2,6,6-tetramethylpiperidin-4-yl)hexamethylenediamine and4-tert-octylamino-2,6-dichloro-1,3,5-triazine,tris(2,2,6,6-tetramethylpiperidin-4-yl)nitrilotriacetate,tetrakis(2,2,6,6-tetramethylpiperidin-4-yl)1,2,3,4-butanetetracarboxylate,1,1′-(1,2-ethylene)bis(3,3,5,5-tetramethylpiperazinone),4-benzoyl-2,2,6,6-tetramethylpiperidine,4-stearyloxy-2,2,6,6-tetramethylpiperidine,bis(1,2,2,6,6-pentamethylpiperidin-4-yl)2-n-butyl-2-(2-hydroxy-3,5-di-tert-butylbenzyl)malonate,3-n-octyl-7,7,9,9-tetramethyl-1,3,8-triazaspiro[4.5]decane-2,4-dione,bis(1-octyloxy-2,2,6,6-tetramethylpiperidin-4-yl)sebacate,bis(1-octyloxy-2,2,6,6-tetramethylpiperidin-4-yl)succinate, thecondensation product ofN,N′-bis(2,2,6,6-tetramethylpiperidin-4-yl)hexamethylenediamine and4-morpholino-2,6-dichloro-1,3,5-triazine, the condensation product of2-chloro-4,6-bis(4-n-butylamino-2,2,6,6-tetramethylpiperidin-4-yl)-1,3,5-triazineand 1,2-bis(3-aminopropylamino)ethane, the condensation product of2-chloro-4,6-di(4-n-butylamino-1,2,2,6,6-pentamethylpiperidin-4-yl)-1,3,5-triazineand 1,2-bis(3-aminopropylamino)ethane,8-acetyl-3-dodecyl-7,7,9,9-tetramethyl-1,3,8-triazaspiro[4.5]-decane-2,4-dione,3-dodecyl-1-(2,2,6,6-tetramethylpiperidin-4-yl)pyrrolidine-2,5-dione,3-dodecyl-1-(1,2,2,6,6-pentamethylpiperidin-4-yl)pyrrolidine-2,5-dione,a mixture of 4-hexadecyloxy- and4-stearyloxy-2,2,6,6-tetramethylpiperidine, the condensation product ofN,N′-bis(2,2,6,6-tetramethylpiperidin-4-yl)hexamethylenediamine and4-cyclohexylamino-2,6-dichloro-1,3,5-triazine, the condensation productof 1,2-bis(3-aminopropylamino)ethane and 2,4,6-trichloro-1,3,5-triazine,4-butylamino-2,2,6,6-tetramethylpiperidine,N-(2,2,6,6-tetramethylpiperidin-4-yl)-n-dodecylsuccinimide,N-(1,2,2,6,6-pentamethylpiperidin-4-yl)-n-dodecylsuccinimide,2-undecyl-7,7,9,9-tetramethyl-1-oxa-3,8-diaza-4-oxo-spiro[4.5]-decane,the condensation product of7,7,9,9-tetramethyl-2-cycloundecyl-1-oxa-3,8-diaza-4-oxospiro-[4.5]decaneand epichlorohydrin, the condensation products of4-amino-2,2,6,6-tetramethylpiperidine with tetramethylolacetylenediureasandpoly(methoxypropyl-3-oxy)-[4(2,2,6,6-tetramethyl)piperidinyl]-siloxane,Oxalamides, such as 4,4′-dioctyloxyoxanilide, 2,2′-diethoxyoxanilide,2,2′-dioctyloxy-5,5′-di-tert-butoxanilide,2,2′-didodecyloxy-5,5′-di-tert-butoxanilide, 2-ethoxy-2′-ethyloxanilide,N,N′-bis(3-dimethylaminopropyl)oxalamide,2-ethoxy-5-tert-butyl-2′-ethoxanilide and its mixture with2-ethoxy-2′-ethyl-5,4′-di-tert-butoxanilide, and mixtures of ortho-,para-methoxy-disubstituted oxanilides and mixtures of ortho- andpara-ethoxy-disubstituted oxanilides, and2-(2-hydroxyphenyl)-1,3,5-triazines, such as2,4,6-tris-(2-hydroxy-4-octyloxyphenyl)-1,3,5-triazine,2-(2-hydroxy-4-octyloxyphenyl)-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine,2-(2,4-dihydroxyphenyl)-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine,2,4-bis(2-hydroxy-4-propyloxyphenyl)-6-(2,4-dimethylphenyl)-1,3,5-triazine,2-(2-hydroxy-4-octyloxyphenyl)-4,6-bis(4-methylphenyl)-1,3,5-triazine,2-(2-hydroxy-4-dodecyloxyphenyl)-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine,2-(2-hydroxy-4-tridecyloxyphenyl)-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine,2-[2-hydroxy-4-(2-hydroxy-3-butyloxypropoxy)phenyl]-4,6-bis(2,4-dimethyl)-1,3,5-triazine,2-[2-hydroxy-4-(2-hydroxy-3-octyloxypropoxy)phenyl]-4,6-bis(2,4-dimethyl)-1,3,5-triazine,2-[4-(dodecyloxy/tridecyloxy-2-hydroxypropoxy)-2-hydroxyphenyl]-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine,2-[2-hydroxy-4-(2-hydroxy-3-dodecyloxypropoxy)phenyl]-4,6-bis-(2,4-dimethylphenyl)-1,3,5-triazine,2-(2-hydroxy-4-hexyloxyphenyl)-4,6-diphenyl-1,3,5-triazine,2-(2-hydroxy-4-methoxyphenyl)-4,6-diphenyl-1,3,5-triazine,2,4,6-tris[2-hydroxy-4-(3-butoxy-2-hydroxypropoxy)phenyl]-1,3,5-triazineand 2-(2-hydroxyphenyl)-4-(4-methoxyphenyl)-6-phenyl-1,3,5-triazine.

In another preferred embodiment the polymerizable liquid crystal mixturecomprises one or more specific antioxidant additives, preferablyselected from the Irganox® series, e.g. the commercially availableantioxidants Irganox®1076 and Irganox®1010, from Ciba, Switzerland.

In another preferred embodiment, the polymerizable liquid crystalmixture comprises a combination of one or more, more preferably of oneor two photoinitiators, for example, selected from the commerciallyavailable Irgacure® or Darocure® (Ciba AG) series, in particular,Irgacure 127, Irgacure 184, Irgacure 369, Irgacure 651, Irgacure 817,Irgacure 907, Irgacure 1300, Irgacure, Irgacure 2022, Irgacure 2100,Irgacure 2959, or Darcure TPO, further selected from the commerciallyavailable OXE02 (Ciba AG), NCI 930, N1919T (Adeka), SPI-03 or SPI-04(Samyang), or preferably combinations thereof, such as SPI-03 andNCI-930.

The concentration of the polymerisation initiator(s) as a whole in thepolymerizable liquid crystal mixture is preferably from 0.5 to 5%, verypreferably from 0.5 to 3%, more preferably 1 to 2%.

Preferably, the polymerisable LC mixture comprises besides one or moreSAPAs, preferably of formula S,

-   -   a) one or more mono-, di- or multireactive polymerisable        mesogenic compounds, preferably of formula P,    -   b) optionally one or more polymerisable mesogenic compounds,    -   c) optionally one or more antioxidative additives,    -   d) optionally one or more adhesion promotors,    -   e) optionally one or more surfactants,    -   f) optionally one or more mono-, di- or multireactive        polymerisable non-mesogenic compounds,    -   g) optionally one or more dyes showing an absorption maximum at        the wavelength used to initiate photo polymerisation,    -   h) optionally one or more chain transfer agents,    -   i) optionally one or more stabilizers,    -   j) optionally one or more lubricants and flow auxiliaries, and    -   k) optionally one or more diluents,    -   l) optionally a non-polymerisable nematic component.

More preferably, the polymerizable liquid crystal mixture comprises,

-   -   a) one or more compounds of formula S,    -   b) one or more, preferably two or more, direactive polymerisable        mesogenic compounds of formula DRM, preferably in an amount, if        present at all, of 10 to 90% by weight, very preferably 15 to        75% by weight, preferably selected from the compounds of formula        DRMa-1,    -   c) optionally one or more, preferably two or more, monoreactive        polymerisable mesogenic compounds of formula MRM, preferably in        an amount of 10 to 95% by weight, very preferably 25 to 85%,        preferably selected from compounds of formulae MRM-1 and/or        MRM-7,    -   d) optionally one or more compounds of formula ND in the        preferably in an amount of 1 to 50%, very preferably from 1 to        40%.    -   e) optionally one or more antioxidative additives, preferably        selected from esters of unsubstituted and substituted benzoic        acids, in particular Irganox®1076, and if present, preferably in        an amount of 0.01 to 2% by weight, very preferably 0.05 to 1% by        weight,    -   f) optionally one or more lubricants and flow auxiliaries,        preferably selected from BYK®388, FC 4430, Fluor N 561 and/or        Fluor N 562, and if present, preferably in an amount of 0.1 to        5% by weight, very preferably 0.2 to 3% by weight, and        optionally one or more photoinitiators.

Preferably, the polymerizable LC mixture is dissolved in a suitablesolvent before providing it on a suitable substrate. Thus, In anotherpreferred embodiment, the polymerizable liquid crystal mixture comprisesone or more solvents, which are preferably selected from organicsolvents. The solvents are preferably selected from ketones such asacetone, methyl ethyl ketone, methyl propyl ketone, methyl isobutylketone or cyclohexanone; acetates such as methyl, ethyl or butyl acetateor methyl acetoacetate; alcohols such as methanol, ethanol or isopropylalcohol; aromatic solvents such as toluene or xylene; alicyclichydrocarbons such as cyclopentane or cyclohexane; halogenatedhydrocarbons such as di- or trichloromethane; glycols or their esterssuch as PGMEA (propyl glycol monomethyl ether acetate), γ-butyrolactone.It is also possible to use binary, ternary or higher mixtures of theabove solvents.

In case the polymerizable liquid crystal mixture contains one or moresolvents, the total concentration of all solids, including the RMs, inthe solvent(s) is preferably from 10 to 60%.

This solution is then coated or printed onto the substrate, for exampleby spin-coating, printing, or other known techniques, and the solvent isevaporated off before polymerisation. In most cases, it is suitable toheat the mixture in order to facilitate the evaporation of the solvent.

The polymerizable liquid crystal mixture can be applied onto a substrateby conventional coating techniques like spin coating, bar coating orblade coating. It can also be applied to the substrate by conventionalprinting techniques which are known to the expert, like for examplescreen printing, offset printing, reel-to-reel printing, letter pressprinting, gravure printing, rotogravure printing, flexographic printing,intaglio printing, pad printing, heat-seal printing, ink-jet printing orprinting by means of a stamp or printing plate.

Suitable substrate materials and substrates are known to the expert anddescribed in the literature, as for example conventional substrates usedin the optical films industry, such as glass or plastic. Especiallysuitable and preferred substrates for polymerisation are polyester suchas polyethyleneterephthalate (PET) or polyethylenenaphthalate (PEN),polyvinylalcohol (PVA), polycarbonate (PC) triacetylcellulose (TAC), orcyclo olefin polymers (COP), or commonly known color filter materials,in particular triacetylcellulose (TAC), cyclo olefin polymers (COP), orcommonly known colour filter materials.

In a preferred embodiment the linearly polarised light is ultravioletlight which enables simultaneous photoalignment of the self assemblingphotoalignment agent and photocuring of the polymerizable liquid crystalmolecules compound.

A self assembling photoalignment agent (SAPA) according to the presentinvention is preferably a compound comprising at least one polar lateralgroup and at least one photoreactive group. Considering theinvestigations for this invention it appears that the polar lateralgroup interacts with the substrate surface thus enabling the SAPA tophase separate from the LC mixture after filling of the LC cell.According to this opinion, the SAPA forms a layer on the substrate whichcan be photoaligned with linearly polarised UV light. The liquid crystalfollows the orientation of the aligned SAPA to give uniform planaralignment across the whole display.

The photoalignment process according to the present invention causes theSAPA to undergo an isomerisation under irradiation with linearlypolarised light of appropriate wavelength. The photoisomerisation is anangle-dependent process, resulting eventually in the photoselection ofSAPA orientations that are preferentially perpendicular to thepolarization of the actinic light and with orientational anisotropycapable of aligning LCs.

The wavelength region of the polarised light is preferably chosen so asto match the absorption spectrum of the SAPA.

In case the alignment is reversible, for example under the influence ofheat or light, it is mandatory to fix the alignment of the SAPA and theLC.

For the production of the polymer films according to the presentinvention, the polymerisable LC mixture is preferably allowed toredistribute on the surface of the substrate. After providing a layer ofthe polymersisable LC Mixture on the substrate, the layer is annealedfor a time between 10 seconds and 1 h, preferably between 20 seconds minand 30 minutes and most preferably between 30 seconds and 5 min. Theannealing is preferably performed at room temperature.

In an alternative embodiment, the annealing is performed at elevatedtemperature, preferably at above 20° C. and below 140° C., morepreferably above 40° C. and below 100° C. and most preferably above 50°C. and below 80° C.

In a preferred embodiment, one or more of the process steps ofannealing, photoalignment and curing of the polymerizable compound isperformed at a temperature above the clearing point of the polymerizableliquid crystal mixture.

During the photoalignment of the polymerizable liquid crystal compounds,anisotropy is induced by exposing the display or the liquid crystallayer to linearly polarised light.

In a preferred embodiment of the present invention the SAPA isphotoaligned in a first step using linearly polarised light and in asecond step the polymerizable liquid crystal compounds are cured usinglinearly polarized or unpolarised UV light.

In another preferred embodiment, the linearly polarised light appliedaccording to the inventive process is ultraviolet light or VIS whichenables photoalignment.

Photoalignment of the SAPA and curing of the polymerizable liquidcrystal compounds can be performed simultaneously or stepwise. In casethe process is split into different steps, the individual steps can beperformed at the same temperature or at different temperatures.

The curing time is dependent, inter alia, on the reactivity of thepolymerisable LC mixture, the thickness of the coated layer, the type ofpolymerisation initiator and the power of the UV lamp. The curing timeis preferably 5 minutes, very preferably 3 minutes, most preferably 1minute. For mass production, short curing times of 30 seconds arepreferred.

A suitable UV radiation power is preferably in the range from 5 to 200mWcm-2, more preferably in the range from 50 to 175 mWcm−2 and mostpreferably in the range from 100 to 150 mWcm⁻².

In connection with the applied UV radiation and as a function of time, asuitable UV dose is preferably in the range from 25 to 7200 mJcm⁻² morepreferably in the range from 500 to 7200 mJcm⁻² and most preferably inthe range from 3000 to 7200 mJcm⁻².

Photopolymerisation is preferably performed under an inert gasatmosphere, preferably in a heated nitrogen atmosphere, but alsopolymerisation in air is possible.

After the photoalignment and curing step(s) a so-called “post-curing”step can optionally be performed by irradiation with UV-light and/orvisible light (both either linearly or unpolarised) at reducedtemperature in order to remove unreacted polymerizable compounds. Thepost-curing is preferably performed at above 0° C. and below theclearing point of the utilized LC mixture, preferably 20° C. and below60° C.° C., and most preferably above 20° C. and below 40° C.

The preferred thickness of a polymerised LC film according to thepresent invention is determined by the optical properties desired fromthe film or the final product. For example, if the polymerised LC filmdoes not mainly act as an optical layer, but e.g. as adhesive, aligningor protection layer, its thickness is preferably not greater than 1 μm,in particular not greater than 0.5 μm, very preferably not greater than0.2 μm.

For example, uniformly planar aligned polymer films of the presentinvention can be used as retardation or compensation films for examplein LCDs to improve the contrast and brightness at large viewing anglesand reduce the chromaticity. They can be used outside the switchableliquid-crystalline cell in an LCD, or between the substrates, usuallyglass substrates, forming the switchable liquid-crystalline cell andcontaining the switchable liquid-crystalline medium (in cellapplication).

For optical applications of the polymer film, it preferably has athickness of from 0.5 to 10 μm, very preferably from 0.5 to 5 μm, inparticular from 0.5 to 3 μm.

The optical retardation (δ(λ)) of a polymer film as a function of thewavelength of the incident beam (λ) is given by the following equation:

δ(λ) = (2πΔ n ⋅ d)λwherein (Δn) is the birefringence of the film, (d) is the thickness ofthe film and λ is the wavelength of the incident beam.

According to Snellius law, the birefringence as a function of thedirection of the incident beam is defined as

Δ n = sin  Θ/sin  Ψwherein sin Θ is the incidence angle or the tilt angle of the opticalaxis in the film and sin Ψ, is the corresponding reflection angle.

Based on these laws, the birefringence and accordingly opticalretardation depends on the thickness of a film and the tilt angle ofoptical axis in the film (cf. Berek's compensator). Therefore, theskilled expert is aware that different optical retardations or differentbirefringence can be induced by adjusting the orientation of theliquid-crystalline molecules in the polymer film.

The birefringence (Δn) of the polymer film according to the presentinvention is preferably in the range from 0.01 to 0.30, more preferablein the range from 0.01 to 0.25 and even more preferable in the rangefrom 0.01 to 0.16.

The optical retardation as a function of the thickness of the polymerfilm according to the present invention is less than 200 nm, preferableless than 180 nm and even more preferable less than 150 nm.

Especially with regard to the in cell application, the polymer filmsaccording to the present invention exhibit a high temperature stability.Thus, the polymer films exhibit temperature stability up to 300° C.,preferably up to 250° C., more preferably up to 230° C.

The polymer film of the present invention can also be used as alignmentfilm for other liquid-crystalline or RM materials. For example, they canbe used in an LCD to induce or improve alignment of the switchableliquid-crystalline medium, or to align a subsequent layer ofpolymerizable liquid crystal mixture coated thereon. In this way, stacksof polymerised LC films can be prepared.

In summary, the polymerised LC films according to the present inventionare useful in optical components like polarisers, compensators,alignment layer, circular polarisers or colour filters in liquid crystaldisplays or projection systems, decorative images, for the preparationof liquid crystal or effect pigments, and especially in reflective filmswith spatially varying reflection colours, e.g. as multicolour image fordecorative, information storage or security uses, such as non-forgeabledocuments like identity or credit cards, banknotes etc.

The polymer films or optical components according to the presentinvention can be used in optical devices such as displays of thetransmissive or reflective type. They can be used in conventional OLEDdisplays or LCDs, in particular LCDs of the DAP (deformation of alignedphases) or VA (vertically aligned) mode, like e.g. ECB (electricallycontrolled birefringence), CSH (colour super homeotropic), VAN or VAC(vertically aligned nematic or cholesteric) displays, MVA (multi-domainvertically aligned) or PVA (patterned vertically aligned) displays, indisplays of the bend mode or hybrid type displays, like e.g. OCB(optically compensated bend cell or optically compensatedbirefringence), R-OCB (reflective OCB), HAN (hybrid aligned nematic) orpi-cell (π-cell) displays, furthermore in displays of the TN (twistednematic), HTN (highly twisted nematic) or STN (super twisted nematic)mode, in AMD-TN (active matrix driven TN) displays, or in displays ofthe IPS (in plane switching) mode which are also known as ‘super TFT’displays. Especially preferred are VA, MVA, PVA, OCB, and pi-celldisplays.

The polymer films according to the present invention are especiallyuseful for a 3D display as described in EP 0 829 744, EP 0 887 666 A2,EP 0 887 692, U.S. Pat. Nos. 6,046,849, 6,437,915 and in “Proceedings othe SID 20th International Display Research Conference, 2000”, page 280.A 3D display of this type comprising a polymer film according to theinvention is another object of the present invention.

The present invention is described above and below with particularreference to the preferred embodiments. It should be understood thatvarious changes and modifications might be made therein withoutdeparting from the spirit and scope of the invention.

Many of the compounds or mixtures thereof mentioned above and below arecommercially available. All of these compounds are either known or canbe prepared by methods which are known per se, as described in theliterature (for example in the standard works such as Houben-Weyl,Methoden der Organischen Chemie [Methods of Organic Chemistry],Georg-Thieme-Verlag, Stuttgart), to be precise under reaction conditionswhich are known and suitable for said reactions. Use may also be madehere of variants which are known per se, but are not mentioned here.

It will be appreciated that variations to the foregoing embodiments ofthe invention can be made while still falling within the scope of theinvention. Alternative features serving the same, equivalent, or similarpurpose may replace each feature disclosed in this specification, unlessstated otherwise. Thus, unless stated otherwise, each feature disclosedis one example only of a generic series of equivalent or similarfeatures.

All of the features disclosed in this specification may be combined inany combination, except combinations where at least some of suchfeatures and/or steps are mutually exclusive. In particular, thepreferred features of the invention are applicable to all aspects of theinvention and may be used in any combination. Likewise, featuresdescribed in non-essential combinations may be used separately (not incombination).

It will be appreciated that many of the features described above,particularly of the preferred embodiments, are inventive in their ownright and not just as part of an embodiment of the present invention.Independent protection may be sought for these features in addition toor alternative to any invention presently claimed.

The invention will now be described in more detail by reference to thefollowing working examples, which are illustrative only and do not limitthe scope of the invention.

The examples below serve to illustrate the invention without limitingit.

EXAMPLES

Utilized RMs

For the following mixtures, the following RMs are utilized:

RM No.

1

2

3

4Utilized SAPA:

Utilized Mixtures

The following mixtures CM-1 and M-1 to 4 are prepared in accordance withthe following table:

CM-1 M-1 M2 M3 M4 % % % % % Mixture [w/w] [w/w] [w/w] [w/w] [w/w]Irganox  0.08%  0.08%  0.08%  0.08%  0.08% 1076 FluorN  0.61%  0.61% 0.61%  0.61%  0.61% 562 RM-1 25.28% 25.03% 23.50% 22.00% 20.00% RM-225.28% 25.03% 23.50% 22.00% 20.00% RM-3  9.78%  9.69%  9.25%  9.00% 6.00% RM-4 38.97% 38.56% 38.06% 36.31% 33.31% SAPA-1  0.00%  1.00% 5.00% 10.00% 20.00%

Irganox1076® is a stabilizer being commercially available (Ciba AG,Basel, Switzerland). FluorN 562 FluorN is a non-reactive, high fluorinecontent, ethylene glycol based polymeric fluorosurfactant commerciallyavailable (Cytonix LLC, Beltsville, USA)

General Method for the Polymer Film Preparation:

The mixture of interest is spin coated at 3000 rpm for 30 s onto a rawglass slide with no alignment layer.

The sample is annealed at 60° C. for 60 s on a temperature controlledhot plate.

The sample is heated to the isotropic phase of the correspondingmixture, e.g. 100° C. for 60 seconds, and then irradiated with linearpolarized light (250-450 nm Omnicure High Pressure Hg Lamp, 30 mW/cm²for 60 s) while being in the isotropic phase.

Experiment 1

Polymer films are produced using the above described method.

The polymer film obtained from mixture CM-1 (CE-1) is compared withpolymer films obtained from mixtures M-1 to M-4 containing differentamounts of SAPA (E-1 to E-4).

Each film is visually inspected for uniform homogeneous alignmentbetween crossed polarizers.

Example CE-1 E-1 E-2 E-3 E-4 Alignment No good good good good Qualityalignment

Retardation for polymer films resulting from mixtures M-1 to M-4 ismeasured at angles of incidence from −60° to 40° at a temperature of 20°C. at a wavelength of 550 nm.

The retardation (R(λ)) of a material can be measured using aspectroscopic ellipsometer, for example the M2000 spectroscopicellipsometer manufactured by J. A. Woollam Co., This instrument iscapable of measuring the optical retardance in nanometres of abirefringent sample e.g. Quartz over a range of wavelengths typically,370 nm to 2000 nm.

A method for carrying out these measurements was presented at theNational Physics Laboratory (London, UK) by N. Singh in October 2006 andentitled “Spectroscopic Ellipsometry, Part 1—Theory and Fundamentals,Part 2—Practical Examples and Part 3—measurements”. In accordance withthe measurement procedures described Retardation Measurement (RetMeas)Manual (2002) and Guide to WVASE (2002) (Woollam Variable AngleSpectroscopic Ellipsometer) published by J. A. Woollam Co. Inc (Lincoln,Nebr., USA). Unless stated otherwise, this method is used to determinethe retardation of the materials, films and devices described in thisinvention.

Angle (°) −60 −40 −20 0 20 40 R(550) of M-1 119.82 131.92 142.56 145.78141.91 131.80 R(550) of M-2 113.83 125.32 135.43 138.49 134.81 125.21R(550) of M-3 110.23 121.37 131.16 134.12 130.56 121.26 R(550) of M-493.46 102.90 111.20 113.71 110.69 102.80

The invention claimed is:
 1. A method for manufacturing a homogeneousaligned polymer film comprising at least the steps of: providing apolymerizable liquid crystal mixture, comprising one or morepolymerizable liquid crystal molecules, wherein the total concentrationof the one or more polymerizable liquid crystal molecules in the liquidcrystal mixture is 85 to 99.9%, and one or more self assemblingphotoalignment agents, on a substrate; irradiating the liquid crystalmixture with linearly polarised light causing photoalignment of thepolymerizable liquid crystal mixture; optionally curing thepolymerizable liquid crystal compounds by irradiation with ultravioletlight, wherein said homogeneous aligned polymer film is manufactured. 2.The method according to claim 1, wherein the one or more self assemblingphotoalignment agents are compounds of formula S,

wherein L^(s) each, identically or differently, denote F, Cl, CN, SCN,SF₅ or a straight-chain, in each case optionally fluorinated, alkyl,alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy oralkoxycarbonyloxy having 1 to 12 C atoms, or a branched, in each caseoptionally fluorinated, alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl,alkylcarbonyloxy or alkoxycarbonyloxy having 3 to 12 C atoms,(Sp^(s))_(r1)-G, Y, or (Sp^(s))_(r1)-PS P^(s) each, independently of oneanother, denote a polymerisable group, Sp^(s) on each occurrence,identically or differently, denote a spacer group, Y denotes (R^(b))₂N-or, RC(O)O—, G denotes —OH or Si(OR^(a))₃, R^(a), R^(b), R^(c) eachdenote, identically or differently, H, a straight chain alkyl with 1 to6 C atoms, or a branched alkyl with 3 to 6 C atoms, r1 denotes 0 or 1,t1, t2 denotes, each independently, 1, 2, 3, 4 or 5, and Z^(s) denotes—N═N—, —CH═CH—, —CH═CH—COO—, —OCO—CH═— CH—, —CO—CH═CH—, or —CH═CH—CO—,wherein one or more H are optionally replaced by halogen.
 3. The methodaccording to claim 1, wherein the one or more self assemblephotoalignment agents are compounds of formula S1,

wherein Y denotes (R^(b))₂N—, R^(c)C(O)O—, or a group Ls, Sp denotes aspacer group, G denotes —OH or Si(OR^(a))₃, R^(a), R^(b), R^(c) eachdenote, identically or differently, a straight chain or branched alkylwith 1 to 6 C atoms, or branched alkyl with 3 to 6 C atoms, LS each,identically or differently, denote P-Sp-, F, Cl, Br, I, —CN, —NO₂, —NCO,—NCS, —OCN, —SCN, —C(═O)NR⁰⁰R⁰⁰⁰, —C(═O)OR⁰⁰, —C(═O)R⁰⁰, —NR⁰⁰R⁰⁰⁰, —OH,—SF₅, optionally substituted silyl, or aryl or heteroaryl with 3 to 12 Catoms, or a straight chain alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl,alkylcarbonyloxy or alkoxycarbonyloxy with 1 to 12 C atoms, or abranched alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxyor alkoxycarbonyloxy with 3 to 12 C atoms, wherein one or more H atomsare optionally replaced by F or Cl, R⁰⁰ and R⁰⁰⁰ each, independently ofone another, denote H, F or a straight-chain or branched alkyl having 1to 12 C atoms, or a branched alkyl having 3 to 12 C atoms, wherein oneor more H atoms are optionally replaced by F, t1, t2 denotes 0, 1, 2, 3or
 4. 4. The method according to claim 1, wherein the totalconcentration of the one or more self assembling photoalignment agentsin the liquid crystal mixture is 1 to 15%.
 5. The method according toclaim 1, wherein the one or more polymerizable liquid crystal moleculesare compounds of formula DRM,P¹-Sp¹-MG-Sp²-P²  DRM wherein P¹ and P² independently of each otherdenote a polymerizable group, Sp¹ and Sp² independently of each otherare a spacer group or a single bond, and MG is a rod-shaped mesogenicgroup.
 6. The method according to claim 1, wherein the one or morepolymerizable liquid crystal molecules are selected from compounds ofthe following formulae,

wherein P⁰ is, in case of multiple occurrence independently of oneanother, an acryl, methacryl, oxetane, epoxy, vinyl, heptadiene,vinyloxy, propenyl ether or styrene group, L is P-Sp-, F, Cl, Br, I,—CN, —NO₂, —NCO, —NCS, —OCN, —SCN, —C(═O)NR⁰⁰R⁰⁰⁰, —C(═O)OR⁰⁰,—C(═O)R⁰⁰, —NR⁰⁰R⁰⁰⁰, —OH, —SF₅, optionally substituted silyl, or arylor heteroaryl with 3 to 12 C atoms, a straight chain alkyl, alkoxy,alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxywith 1 to 12 C atoms, or a branched alkyl, alkoxy, alkylcarbonyl,alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy with 3 to 12 Catoms, wherein one or more H atoms are optionally replaced by F or Cl,R⁰⁰ and R⁰⁰⁰ each, independently of one another, denote H, F or astraight-chain alkyl having 1 to 12 C atoms, or branched alkyl having 3to 12 C atoms, wherein one or more H atoms are optionally replaced by F,r is 0, 1, 2, 3 or 4, x and y are independently of each other 0 oridentical or different integers from 1 to 12, Z is, each independently,0 or 1, with z being 0 if the adjacent x or y is
 0. 7. The methodaccording to claim 1, wherein the one or more polymerizable liquidcrystal molecules are of formula MRM,P¹-Sp¹-MG-R  MRM wherein P¹ denotes a polymerizable group, Sp¹ is aspacer group or a single bond, MG is a rod-shaped mesogenic group, R isF, Cl, Br, I, —CN, —NO₂, —NCO, —NCS, —OCN, —SCN, —C(═O)NRXRY, —C(═O)X,—C(═O)ORX, —C(═O)RY, —NR*RY, —OH, —SF₅, optionally substituted silyl, ora straight chain alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl,alkylcarbonyloxy or alkoxycarbonyloxy with 1 to 12 C atoms, or abranched alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxyor alkoxycarbonyloxy with 3 to 12 C atoms, wherein one or more H atomsare optionally replaced by F or Cl, X is halogen, and R^(x) and R^(y)are independently of each other H or alkyl with 1 to 12 C-atoms.
 8. Themethod according to claim 1, wherein the one or more polymerizableliquid crystal molecules are selected from the following formulae,

wherein P⁰ is, in case of multiple occurrence independently of oneanother, an acryl, methacryl, oxetane, epoxy, vinyl, heptadiene,vinyloxy, propenyl ether or styrene group, L is P-Sp-, F, Cl, Br, I,—CN, —NO₂, —NCO, —NCS, —OCN, —SCN, —C(═O)NR⁰⁰R²⁰⁰⁰, —C(═O)OR⁰⁰,—C(═O)R⁰⁰, —NR²⁰⁰⁰⁰⁰, —OH, —SF₅, optionally substituted silyl, or arylor heteroaryl with 3 to 12 C atoms, or a straight chain alkyl, alkoxy,alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxywith 1 to 12 C atoms, or a branched alkyl, alkoxy, alkylcarbonyl,alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy with 3 to 12 Catoms, wherein one or more H atoms are optionally replaced by F or Cl,R⁰⁰ and R⁰⁰⁰ each, independently of one another, denote H, F or astraight-chain or branched alkyl having 1 to 12 C atoms, or a branchedalkyl having 3 to 12 C atoms, wherein one or more H atoms are optionallyreplaced by F, r is 0, 1, 2, 3 or 4, x and y are independently of eachother 0 or identical or different integers from 1 to 12, Z is, eachindependently, 0 or 1, with z being 0 if the adjacent x or y is 0, R⁰ isan alkyl, alkoxy, thioalkyl, alkylcarbonyl, alkoxycarbonyl,alkylcarbonyloxy or alkoxycarbonyloxy with 1 or more C atoms or denotesY⁰, Y⁰ is F, Cl, CN, NO₂, OCH₃, OCN, SCN, SF₅, or a mono- oligo- orpolyfluorinated alkyl or alkoxy with 1 to 4 C atoms, Z⁰ is —COO—, —OCO—,—CH₂CH₂—, —CF₂O—, —OCF₂—, —CH═CH—, —OCO—CH═CH—, —CH═CH—COO—, or a singlebond, A⁰ is, in case of multiple occurrence independently of oneanother, 1,4-phenylene that is unsubstituted or substituted with 1, 2, 3or 4 groups L, or trans-1,4-cyclohexylene, u and v are independently ofeach other 0, 1 or 2, W is 0 or 1, and wherein the benzene andnaphthalene rings are optionally substituted with one or more identicalor different groups L.
 9. The method according to claim 1, wherein thetotal concentration of the one or more polymerizable liquid crystalmolecules in the liquid crystal mixture is 90 to 99.9%.
 10. The methodaccording to claim 1, wherein the polarised light is ultraviolet light.11. The method according to claim 1, wherein the polarised light is VISlight.
 12. A polymer film obtainable by the method according to claim 1.13. An optical component comprising a polymer film according to claim12.
 14. An optical device comprising a polymer film according to claim12.
 15. The method according to claim 1, wherein the one or morepolymerizable liquid crystal molecules are compounds of formula DRM,P¹-Sp¹-MG-Sp²-P²  DRM wherein P¹ and P² independently of each otherdenote a polymerizable group, Sp¹ and Sp² independently of each otherare a spacer group or a single bond, and MG is a rod-shaped mesogenicgroup of formula MG-(A¹¹-Z¹¹)_(n)-A¹²-  MG A¹¹ and A¹² denote, in case of multipleoccurrence independently of one another, an aromatic or alicyclic group,which optionally contains one or more heteroatoms selected from thegroup consisting of N, O and S, and is optionally mono- orpolysubstituted by L¹¹, L¹¹ is P-Sp-, F, Cl, Br, I, —CN, —NO₂, —NCO,—NCS, —OCN, —SCN, —C(═O)NR⁰⁰R⁰⁰⁰, —C(═O)OR⁰⁰, —C(═O)R⁰⁰, —NR⁰⁰¹⁰⁰⁰, —OH,—SF₅, optionally substituted silyl, or aryl or heteroaryl with 3 to 12 Catoms, a straight chain alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl,alkylcarbonyloxy or alkoxycarbonyloxy with 1 to to 12 C atoms, or abranched alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxyor alkoxycarbonyloxy with 3 to 12 C atoms, wherein one or more H atomsare optionally replaced by F or Cl, R⁰⁰ and R⁰⁰⁰ each, independently ofone another, denote H, For a straight-chain or branched alkyl having 1to 12 C atoms, or a branched alkyl having 3 to 12 C atoms, wherein oneor more H atoms are optionally replaced by F, Z¹¹ denotes, in case ofmultiple occurrence independently of one another, —O—, —S—, —CO—, —COO—,—OCO—, —S—CO—, —CO—S—, —O—COO—, —CO—NR⁰⁰—, —NR⁰⁰—CO—, —NR⁰⁰—CO—NR⁰⁰⁰,—NR⁰⁰—CO—O—, —O—CO—NR⁰⁰—, —OCH₂—, —CH₂O—, —SCH₂—, —CH₂S—, —CF₂O—,—OCF₂—, —CF₂S—, —SCF₂—, —CH₂CH₂—, —(CH₂)_(n1), —CF₂CH₂—, —CH₂CF₂—,—CF₂CF₂—, —CH═N—, —N═CH—, —N═N—, —CH═CR⁰⁰—, —CY¹═CY²—, —C═C—,—CH═CH—COO—, —OCO—CH═CH— or a single bond, Y¹ and Y² independently ofeach other denote H, F, Cl or CN, n is 1, 2, 3 or 4, and n1 is aninteger from 1 to
 10. 16. The method according to claim 1, wherein theone or more polymerizable liquid crystal molecules are of formula MRM,P¹-Sp¹-MG-R  MRM wherein P¹ denotes a polymerizable group, Sp¹ is aspacer group or a single bond, MG is a rod-shaped mesogenic group offormula MG-(A¹¹-Z¹¹)_(n)-A¹²-  MG A¹¹ and A¹² denote, in case of multipleoccurrence independently of one another, an aromatic or alicyclic group,which optionally contains one or more heteroatoms selected from thegroup consisting of N, O and S, and is optionally mono- orpolysubstituted by L¹¹, L¹¹ is P-Sp-, F, Cl, Br, I, —CN, —NO₂, —NCO,—NCS, —OCN, —SCN, —C(═O)NR⁰⁰¹⁰⁰⁰, —C(═O)OR⁰⁰, —C(═O)R⁰⁰, —NR⁰⁰¹⁰⁰⁰, —OH,—SF₅, optionally substituted silyl, or aryl or heteroaryl with 3 to 12 Catoms, a straight chain alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl,alkylcarbonyloxy or alkoxycarbonyloxy with 1 to 12 C atoms, or abranched alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxyor alkoxycarbonyloxy with 3 to 12 C atoms, wherein one or more H atomsare optionally replaced by F or Cl, R⁰⁰ and R⁰⁰⁰ each, independently ofone another, denote H, For a straight-chain or branched alkyl having 1to 12 C atoms, or a branched alkyl having 3 to 12 C atoms, wherein oneor more H atoms are optionally replaced by F, Z¹¹ denotes, in case ofmultiple occurrence independently of one another, —O—, —S—, —CO—, —COO—,—OCO—, —S—CO—, —CO—S—, —O—COO—, —CO—NR⁰⁰—, —NR⁰⁰—CO—, —NR⁰⁰—CO—NR⁰⁰⁰,—NR⁰⁰—CO—O—, —O—CO—NR⁰⁰—, —OCH₂—, —CH₂O—, —SCH₂—, —CH₂S—, —CF₂O—,—OCF₂—, —CF₂S—, —SCF₂—, —CH₂CH₂—, —(CH₂)_(n1), —CF₂CH₂—, —CH₂CF₂—,—CF₂CF₂—, —CH═N—, —N═CH—, —N═N—, —CH═CR⁰⁰—, —CY¹═CY²—, —C═C—,—CH═CH—COO—, —OCO—CH═CH— or a single bond, Y¹ and Y² independently ofeach other denote H, F, Cl or CN, n is 1, 2, 3 or 4, n1 is an integerfrom 1 to 10, R is F, Cl, Br, I, —CN, —NO₂, —NCO, —NCS, —OCN, —SCN,—C(═O)NR*RY, —C(═O)X, —C(═O)ORX, —C(═O)RY, —NR*RY, —OH, —SF₅, optionallysubstituted silyl, or a straight chain alkyl, alkoxy, alkylcarbonyl,alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy with 1 to 12 Catoms, or a branched alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl,alkylcarbonyloxy or alkoxycarbonyloxy with 3 to 12 C atoms, wherein oneor more H atoms are optionally replaced by F or Cl, X is halogen, andR^(x) and R^(y) are independently of each other H or alkyl with 1 to 12C-atoms.